Circuits FAQ

This is the Archive of Electronics Design related Question & Answers. Ask Questions at EE BBS FAQ. To get a project designed by delabs visit Design Service.

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Friday, December 04, 2020

Single Digit Voltmeter Improvements

I would like to improve that circuit of a single digit voltmeter, I want to make it measure voltage from -9 V to +9 V but I don't have any idea.so would you please give me an idea.

I would like it if we could finish that circuit soon ,because there someone who would like to sponsor me with money to buy the components for that circuit before he takes a business trip.so please when you have an idea please talk to me so that we can finish in soon.

TM


This is the best configuration for now. maybe when i have time i will complete this for you.
Single Digit Voltmeter Improvements You have to put some efforts yourself to create this gizmo. That will also help you learn.

delabs

Tuesday, December 01, 2020

Ultrasonic Range Meter

I have attached a document of the circuit explanation of my ultrasonic range meter. But now I want to know if Im going to insert with in series with my 1M ohm resistor for the feed back of the op-amp to tune it for perfect 100db if the pot is not going to cause a bit of inductance due to the high frequency. 

Can you please help me with some calibration features/tips I can added into my circuits Thanks and regards 

WS SA


Circuit explanation of Ultrasonic Range Meter unit 

oscillation circuit to control the sending-out time of the ultrasonic pulse. The time of the oscillation pulse can be calculated by the following formula. Actually, with the error of the parts, it is different from the calculation a little. 

Ultrasonic Range Meter

Circuit explanation for Ultrasonic Range Meter

The ultrasonic signal which was received with the reception sensor is amplified by 1000 times(60dB) of voltage with the operational amplifier with two stages. It is 100 times at the first stage (40dB) and 10 times (20dB) at the next stage.

Digital Music Player with Amplifier

I need to know as making an amplifier with a port USB as music storage in a memory Flash, which circuit integrated as independent DAC can use could give me some diagram that could use. Greetings and respects 

Gonzalez RC


This is a very old emial from my thunderbird archive.

Digital Music Player with Amplifier
 

Try this MP3 Player with LCD Display

This project is a stand alone MP3 player, designed for home, car, or portable use. It plays a group of MP3 files stored on a standard or laptop IDE hard disk drive... hundreds of hours using even today's low-cost drives.

The firmware is available under the GPL, for anyone who want to really customize the player. High quality audio output is provided by a 24 bit DAC, using both standard line-level outputs and an amplified headphone output.

Sunday, November 08, 2020

Digital weight Indicator - Strain Gauge

I need some details of a digital weight Indicator.
mail from CA

Digital Weight Indicators and Weighing Scales use Strain Gauges mounted on a Stressed Beam, Cantilever or Plate which is also Elastic, means springs back to old shape.

Digital weight Indicator - Strain_gauge

Strain Gauges are bonded to these plates and connected in a Wheatstone bridge circuit. The output of these are very low, as less as 5mV. These are amplified close to the sensor and usable outputs in volts, like 0-10V are used to display the parameter or control the systems.

Fluids Weights are measure with pressure sensors also. Which also have a mini strain gauge or piezoelectric sensor to convert weight to millivolts.

delabs

Wednesday, November 04, 2020

What is Saturation in Transistors

Date 8/30/06 Simon and delabs
Simon: hello,
delabs: hello

Simon: we have many meanings for saturation,
delabs: means turning on, also means no longer linear, or it is got fixed up, not varying in accordance to any formula

Simon: that is what is concluded of. but we just wanted to be sure.
delabs: like you put salt in water. after some time no more salt can be dissolved, that is the state of saturation, In Electrical, no more relationship with V - I - R. Any increase in voltage or reduction it is same

Simon: thanks
delabs: anytime

What is Saturation in Transistors

Bipolar transistors are so named because their operation involves both electrons and holes. These two kinds of charge carriers are characteristic of the two kinds of doped semiconductor material; electrons are majority charge carriers in n-type semiconductors,

Sunday, November 01, 2020

Building a mV Milli-Volt Calibrator Source

Hi, I am trying to build this mV source that you have drawn on your site. It requires a 5vdc power source with a 1k resistor in line with a 10K pot. Your schematic shows also with the pot a 10k resistor and a 100E component which I have no idea what that is.

My question to you is... does the 10K pot include the 10K resistor and the 100E component or are they separate from the pot? If they are separate, what is the 100E component?

Thanks, KN USA

Dear KN

I would like to know the Circuit File you were referring, i have many on my site for instruments.  Let us understand the Theory so you can build your own.

First - You need a Regulated Power Supply for these circuits to be accurate enough. We do not need things like 0.01% for Industrial Electronics or Field Calibration. You can always keep one of these accurate ones in your Lab.

Building a mV Milli-Volt Calibrator Source 

Second - Now to bring down the Voltage of say 5V to mV, we need to Attenuate right. An attenuator contains Two Resistors. The High Value - like 1K is a Fixed MFR 1% Resistor. This faces the 5V and Then comes a Multiturn Pot, preferably Bourns or Spectrol 10 turn, This is 10K. These two form just the One part of the attenuator.

See another design here  Current Source mA for calibration

Monday, October 12, 2020

Up-Down counter-timer

(A question answer thread of delabs.net, nearly a decade old)

Presettable Up-Down counter-timer

I am looking for a schematic for a pre settable Up/Down counter that I can build for my church. It needs to be 5 decades. From 0:00:00 to 9:59:59. I ran across your web pages while searching for such a schematic. Can you help me out?

EE



Presettable Up-Down counter-timer-Answer

It appears from the "9:59:59 " you have mentioned, what you need is a timer.It it a count up and count down timer you need, like a clock ?

Can you explain to me how you plan to use this circuit in the church.Visit the links below and see if that is what you want.

delabs


Presettable Up-Down counter-timer-Reply 

Thanks for the links. What I need this count down timer for is to allow speakers at the church to know how much time is remaining of their presentation. All of our speakers are taped for later use or review. The speakers giving the presentation usually go over their time limits for the audio tapes. With this unit I am trying to build time can be entered by preset thumbwheel switches. The counter is then started and times out when the counter reaches 0:00:00.

What makes this count down timer different is there will be two seperate displays. A one inch set of seven segment LED's will be in the main console with the rest of the logic. There will also be a 2.5 inch set of seven segment displays remotely connected (anout 3 feet away). The large displays will be what the speakers will see. The small displays will be in the control booth.

I already have the following items gathered up. I am hoping to use these components if I am able. I have the MC14029, the MC14513, the Allegro UDN2597A (to drive the large LED's), the Dallas Semi DS32KHz time base, the MC14020, the MC14013, the large and small LED displays, and the thumbwheel switches (set to 9:59:59 maximum)

I also have some MC14011, MC14490 (Hex Debounce Switch Controller, MC14049, and the R's and C's necessary to complete the circuit.

Does this explain what I am trying to do? I think the MC14029 counters can be used to do all the counting and store the preset values. All I have to do is add the reset at 6 for the tens of seconds and the tens of minutes. However, I don't know how to connect the logic?

The DS32KHz, MC14020 and MC14013 will generate the 1 Hertz (1PPS) signal. That is about all I currently have. That is why I need some help

EE


Presettable Up-Down counter-timer-Answer

below are two circuits in pdf format see if they are ok see... Digital Circuits-2

Circuit 1 - Digital Timer Clock With Preset using Thumbwheel switch.


Circuit 2 - 1 Hz or 1 pps crystal clock using CD4060 and 32768 Hz Crystal.


They have not been tested much... The 4513 control pins 8-4-5-3 connections verify, as i did not get the datasheet.

the circuits will work as concepts are right, but some tweaks in R C values may be required.
the R C values can only be corrected if you have problem in making it work.

the main problem in the R C values may be related to "the reset at 6 for the tens of seconds and the tens of minutes". tell me what changes you may want. this is a presettable count down timer upto 99.59.59 hours.minutes.seconds

delabs

Temperature Meters with Analog Recorder Output

I would like to know if you offer a monitoring solution that will constantly measure ambient (air) temperature (say, 0 to 150°F), and provide a corresponding DC voltage output of either 100 mV, 1 V, 5 V, or 10 V. Do you make a unit that can be configured to do this?

Mail From JPE - WV - US


Analog outputs were very popular as they are inputs to Strip Chart Recorders, Later they had an extra use for PC Based Data Acquisition, data Loggers and PLC. Now we have Instruments with digital and wireless outputs too.

Temperature Meters - DP116 - Omega
 
Economical 3/64 DIN panel meter that has a full size 0.56" green or red LED display, with a built-in analog output and display hold capability. 3 1 /2 Digit Display.

Features Include
  • Thermocouple and RTD Input
  • Full-Size 0.56" (14.2 mm) LED Display
  • Analog Output Standard
  • 1 /8 DIN Panel Adaptor Standard

Economical Digital Meters DP18 - Omega

Economical Digital Meters DP18 - Omega

The DP18 series is a complete family of panel meters with input cards for voltage, process and temperature measurement and control. The signal conditioners for voltage will measure ac or dc voltages or true RMS.

Modular Design, Options for Alarms, Analog Output of Communications, 3 1/2-Digit LED Available in Red or Green Displays

delabs

Saturday, October 10, 2020

HV low current device for testing

New device and needed E-instrumentation > > Have you a controlled e.g. 0-10 kV and 0-100 mA device

MR EU


HV low current device delabs

Do you mean a Variable 0-10 kV with 0-100 mA Current Variation.

Yes, i have made such supplies for Testing Capacitor Insulation long ago. Though The limit of current was around 10mA. What you are indicating is a 1 Killowatt HV supply. Needs safety Precautions. 

delabs

Thursday, September 17, 2020

A Button and four LED Lights

Need a design - Simple one button push button to turn on 4 different LED (3mm Dome) every time you press the button. 

 JE USA


Attached is a circuit file that might work for you. Or make it simpler combining it with the circuit shown below.  555 Oscillator and Running Lights

A Button and four LED Lights

Make a monostable with 555 as shown here - 555 Timer based Circuits  -  and output it to a 4017 with above info, i am sure you can build or design what you want.

 delabs


Temperature control for CPU

My name is IS and I am looking for somebody to design and build a simple circuit that controls a small computer fan using either a 120V plugin or a battery using a temperature switch...

In other words I would give you the set point and at that temperature it would turn on the fan and when it drops below the set point it turns off the fan.. the temperature would have to be measured using a contact type measuring device like a thermocouple or thermistor.

Mail from IS Brazil

See Craig's thermostat circuits

Try this One Chip solution from Maxim Semiconductor - MAX6641 temperature sensor and fan controller - 

https://www.maximintegrated.com/en/products/sensors/MAX6641.html


MAX6641 temperature sensor and fan controller

"Accurately measures the temperature of its own die and the temperature of a remote pn junction. The device reports temperature values in digital form using a 2-wire serial interface. The remote pn junction is typically the emitter-base junction of a common-collector pnp on a CPU, FPGA, or ASIC."

Some of my circuits are here Industrial Process Control Circuits

delabs

Wednesday, September 09, 2020

Motor driver H-Bridge partial

I envision a design based on the ST TD340 (page 19 of attached spec.) utilizing the power MOSFET IRF3709S (attached spec.) with external PWM-Signal (provided), separate external controller supply 20-30VDC (provided) power supply for H-Bridge up 20VDC 50A (provided) with screw-terminal type connections for control and power enclosed in a (preferably) DIN-Rail mountable enclosure that would be housed in a control cabinet (dry, 30-40C)

TM USA


This part below means that you have a 20V-50A DC supply which will power this system ?

Motor driver  H-Bridge partial


"50 amp power supply with 6-18v regulator in a Board size 72mmX120mm"  separate external controller supply 20-30VDC power supply for H-Bridge up 20VDC 50A

Saturday, August 15, 2020

Battery Boost Circuits

(This is a thread of my messenger many years ago - you will be able to notice text communication is quite difficult. sometimes even verbal expression will not specify the need, We need clear drawings and specs)

Sam: I was going thrugh some IC like MAX8880/MAX8881, can u help me with using that with input from my batteries?

dapj: let me see

Sam: It's datasheet says that Supply current [Iin] = 10uA max does it mean it will draw a max of 10uA from my battery?

dapj: it looks like it will work from 2.5 to 12V and it can give you a 5v out 200ma

Sam: Exactly!

dapj: is 5V enough 200mA too, but it cannot boost voltage

Sam: my concern is with my input. What about using rechargeable batteries [4x1, 2100mAh] to act as input to this IC. will it consume 10uA if I do so while my load to the output may vary from 100mA to 200uA

Battery Boost Circuits Max8880

dapj: if you want 5V you need to feed this atleast 5.5V this chip does not consume anything (the uA is Standby consumption )but it is not a voltage doublet or a charge pump

Sam: OK, I need to feed it anything between 5.5 -12V, Do we get recharge battery near about 2V, 2100mA

dapj - a 12 v battery can be recharged when 11.8V is reached it may charge upto 12.8 V in Li ion

Fast, smart NiCD/NiMh battery charger - The MAX713 is designed for NiCd batteries, while the 712 is for NiMh batteries.

Friday, August 14, 2020

Electronic Fifteen LED Roulette

The following was submitted on July 11th, 2007. Message: I want to combine Ne555 with 74154 IC.The indication of the outputs must be shown with LED's but up to so far it need 15 outputs ,is it possible the way i did? if not i will need your assistance

Mail from CY

LED running lights are used to decorate Christmas Trees, Festival Surroundings and even  Buildings. A Clock and a counter are basically required. Many LEDs can be used in parallel with driver transistors. Upto 15 count is is good enough. Many colors can be used and with a PWM or VCO you can make it Audio or Music effects lights like strobe lights.

Electronic Fifteen LED Roulette

Electronique RĂ©alisations - Roulette

Multi-Colored LEDs and drivers and even PIC microelectronics with Visual Effects in the form of ROM tables can make Alphabets and Numbers appear in LED arrays. Some have made Mini Ocillosocpes and Toy Spectrum Analyzers too in LED DOT Matrix Arrays.
LED Sequencer Circuit

The above circuit is another variation of a basic LED sequencer circuit. Note again the use of the 555 as a clock. The 555 is likely one of the most versatile chips ever invented. The output of the 555 is coupled to a 4017 Decade Counter Divider another very widely used chip

555 and CD4017 Running Lights
The 555 clocks 4017 counter and it counts and Ten LEDs indicate the counts. This can be used as a Sequential timer or for generating staircase waveform.

delabs

Tuesday, August 11, 2020

Noise and Hum in Audio Circuits

"I currently have a car stereo set that i use as an amplifier in my living room. but my main problem is that i a lot of noise hum when ever it is on especially when there happens to be a drop in the supply Voltage. i decided to use a voltage regulator and capacitor across (1600uF)...but it only reduced the hum a little. how can i completely eliminate the noise". - Question  by FP

Answer by delabs 

Ensure that the power supply has a full wave or bridge rectifier. If power supply transformer is say 12-0-12 two diodes must be there and a center tap ground OR If a square or round bridge is used with four leads or four diodes, then it is fine. Half wave rectification or a blown or leaky diode can cause this problem. Put all the filter caps you want and add a series choke as well the better the power supply the audio will be good.

Noise and Hum in Audio Circuits

The power supply transformer rating - voltage and current both may need to be boosted. Some very low budget transformers do not use CR-GO plates for lamination (i think it is Cold Rolled Grain Oriented ). They use plain thick metal plates without coating and hence hysteresis and eddy current both cause problems. Then you have ground loop hum and noise of semiconductors, the speaker ground and amplifier ground carry current and they should be directly connected to power supply ground, These you can understand by looking at these pages......

Tuesday, July 07, 2020

Microcontroller and SBC in Real World

details required for... Atmels 89C52 Microcontroller A/D D/A converter Keypad LCD display(Or LED Display) 5V Regulated power supply. Temperature & Humidity controller using PID control algorithm implemented using Atmel's 89C52 microcontroller for a AHU unit ( Analog Input from the sensor(4 wire) 0-10v dc & Output from Microcontroller is 4-20mA to the Actuator through a DAC converter).

The Temperature & Humidity to be controlled are 24±1 degree Celsius and 55%±2% Rh respectively. provide me with good LINKS.

mail from SA

Get a sensor that gives a 0-10V or 4-20mA proportional to RH% and Temp deg C. what you need to do now is to select a A/D and a D/A for a real world interface

you can visit these links.......

DigiThermo Wichit Sirichote

DigiThermo 0-100.0 °C Wichit Sirichote

Build your own a laboratory instrument for measuring time and temperature. The DigiThermo demonstrates the use of 'C' language, a dual-slope converter, LCD interfacing, and digital filtering as well..

The Assembly language program for this may be the complex, due to PID. and my uC pages micro-delabs also in my other pages you can find theory on PID etc, in them i have MCS51 code for 2 setpoint process controller.

delabs

Other uC projects sites links

Temperature and Humidity Meter -  This project is a combined temperature and humidity meter. It is an improvement on my PIC-based humidity meter and my PIC and AVR thermometers. I use an ATmega164, which as lots of I/O and memory.
    Temperature and humidity measurements with the AVR web-server- The tuxgraphics Ethernet board has a lot of general purpose IO pins where external hardware such as sensors can easily be attached. In this example we use the sensirion sht11 sensor to measure temperature, humidity and calculate the dew point.

    Working with SMD and SMT PCB

    One thing tho, i would like to request you to send me some procedures on how to work with surface mount devices (SMD's). I cant get the IC as DIP so i have no choice but improvise an SMD. What is your most professional advice on this? Is it possible you could help me with any procedures for using an SMD on a PCB circuit?.

    mail from CM

    Study These Links.........

    fpga4fun.com - SMD Surface Mount Device and SMT Surface Mount Technology

    you may need a big tabletop magnifier with light and a fine tip soldering iron to get started. It may be difficult and needs a lot of practice, but many people are able to do it.

    Surface-mount technology - Wiki

    Surface-mount technology - Wiki

    An SMT component is usually smaller than its through-hole counterpart because it has either smaller leads or no leads at all. It may have short pins or leads of various styles, flat contacts, a matrix of solder balls (BGAs), or terminations on the body of the component.

    Introduction to Surface Mount Technology and Surface Mount Devices

    By Dean F. Poeth, II, Ph.D., P.E., C.Mfg.E.
    For the Small Manufacturer and Hobbyist: Prototype Manufacturing, Rework, and Repair Techniques

    SMDs have improved performance over through-hole components due to their smaller size, shorter internal leads, and smaller board layouts. These factors reduce the circuit’s parasitic inductance and capacitance. SMDs can also be more cost effective than traditional through-hole components due to the smaller board size, fewer board layers, and fewer holes.

    Hints and Tips for using Surface Mount Technology (SMT) 

    What is Surface Mount Technology? Put Simply - It is a type of electronic component
    package. Most electronic components can be divided into two categories - through hole (TH)
    and surface mount (SM). Through-hole components have been used for many years and are
    designed to be loaded on one side of a printed circuit board (PCB) and soldered on the other.
    SM components are designed to be loaded and soldered on the same side of the PCB.

    Luke Enriquez. Rev 1.3. August 2001.
    VK3EM PO Box 98, Kerrimuir, Vic. 3129. Australia

    delabs

    Datasheets and IC Application Notes

    where can I find on IC data and their application?  mail from EA

    Answer by delabs

    Vintage DataBooks are a valuable source of Electronic Product Design Ideas. Study the Applications.

    Folkscanomy Electronics: Books on Electronics, Circuits and Processors 

    You will also find Radio Electronics and many other Datasheets. Even of firms that do not exist now.
    Datasheets and IC Application Notes

    One of the books here is The " Intersil Hot Ideas" - This was my Mentor Book These helped me build Intelligent Instruments in the 80s. Intersil( GE) was in advanced CMOS before anybody else. They made the smartest chips when the Microprocessors were being examined Skeptically by engineers. (At that time Microprocessors needed many support chips and consumed huge power only later CMOS uC came)

    See also delabs Resources i have created as a reference for such doubts (2007)

    Friday, June 12, 2020

    Mains Voltage Stabilizer Step up Circuit

    i kinda found myself in a place where the voltage is so low (80v-110vAC) and i need to boost it up to 220v so what can i do? i have a burnt stabilizer (that is the electronics part) so i need the electronics circuit to replace the burnt one can Anybody help?

    post by FP



    here is a circuit i made for you, i am not sure it will work, i hope it will help you learn. part of these ideas are over 20 years old. Stabilizer Circuit

    Stabilizer Step up 230V AC 500VA

    This circuit is a design i did, not tested by me as yet. It can Stabilize Mains voltage to around +/- 10% . It can be used for both 110V AC or 220V AC inputs with modifications. The Output is 220V AC. There is an overload, under voltage and over voltage trip circuit. With some tweaks and modifications it might work.

    Solid-State Stabilizer Step up 110V AC


    This circuit is a design concept, not tested by me and i did it just to explain some ideas. The circuit uses opto-coupler MOC3041 of Motorola and the Triac BTA-16-600 of ST as a solid state switch or relay. It also uses the LM324 quad opamp from National Semiconductor which is low power and single supply. As the MOC3041 switches the Triac at zero crossover there is no inter-winding short of transformer on crossover hopefully, the control circuit is designed in such a way that more than one triac will not be turned on at a time, i would like you to give feedback.

    One more circuit, this is a bit complicated and it is not tested, it may not work that easy, just refer it to make your own design, it is just a bit of theory and my experience, i may be wrong at a few places.

    Electric Circuits

    delabs

    Tuesday, June 09, 2020

    Lamp Dimmer DC with L296

    I need a simple circuit to drive a 12v DC (4amp) light. But, it needs to dim to 25% over a specified amount of time. Basically it needs to hold at 25% (4v) for a few seconds then fade and increase to 100%(12v) , hold for a second then fade back to 25%.

    Here are the electrical specs: - Input 12vDC @ 5amps - Output from 4vDC to 12vDC (amp draw may be as little as 1 amp or as much as 4.5) - Only 1 potentiometer is used to vary the rate at which the voltage changes from 4-12 - It must increase and decrease voltage in a very smooth way, so that it fades the light to 100% and then back down to 25%

    mail from JR



    I have a circuit in my website that may serve your purpose, visit Power Supplies Section.

    There may be some documentation errors in my circuits. If you are used to building and troubleshooting circuits then it is ok.

    Switching Battery Charger with L296

    Switching Battery Charger with L296

    L296 is a switch mode power controller here. In this NTE327 or 2N5038 is used to boost the current output. This transistor is both high current and fast switching. U1A, LM358 measures the load current by reading the voltage across shunt R6 and compared to a current limit setting at R14 using U1B to give a load current control. R7-R8 give a voltage feedback for voltage limit.

    delabs

    Tuesday, June 02, 2020

    RS485 Modbus - Wireless Interface

    I am working on alarm systems and would like assistance in designing wireless link for the unit, ie sensors to control panel, control panel to monitoring station.

    I noticed most of the circuits available on your sites are FM 88 - 108 MHz, which would definitely cause interference. Can you please assist me with this final part of my system.

    mail from RT

    i would like to know........... The wireless link distance of Transmitter and receiver. The frequency range you want like FM 'n' MHz Are you aware of the regulations of wireless transmission.

    What band is allowed in your country and what distance. what type of data needs to be transmitted. If this is for process control, RF should be avoided if possible. You should use 4-20mA current loops, RS485 or IR optics.

    delabs


    You can study these pages ...........

    Bridging the gap between Modbus/TCP and Foundation Fieldbus

    Foundation Fieldbus

    Foundation Fieldbus is a power-ful process automation system which offers numerous advan-tages over conventional techno-logies in terms of production quality and serviceability. But migrating to Foundation Fieldbus often entails changing the entire existing control technology - all the way to the managment level.

    Modbus Communication Protocol Suite

    "The OMWT-XREC-MOD Wireless Transceiver uses an embedded 100-milliwatt frequency hopping wireless modem that provides communication between a local RS-485 network and a remote network of RS-485 connected devices. The OMWT-XREC- MOD will automatically sense the direction of data flow and switch the RS-485 and radio devices accordingly."

    with a RS485 and Modbus Network you can do it.

    delabs

    Thursday, April 09, 2020

    Electronics Work Bench

    How can I get a software for an electronics work bench for my pc.

    mail from EA

    I did not understand about the 'electronics work bench' pc based instrument. Try simulation based virtual lab software.

    delabs

    TINA is a powerful yet affordable circuit simulator for analog spice circuit simulation, digital and mixed circuit simulation


    this may be what you want....i am not sure.....have a look. "Tina Pro - The Complete Electronics Lab Edison - Multimedia Lab for Exploring Electronics" ...   also CircuitMaker which you may know.

    CircuitMaker Student Edition

    Ssimulation program.... helpful for learning about circuits, testing designs or analyses, and even just drawing schematics for reports.

    delabs

    Monday, April 06, 2020

    Cypress PSoC Mixed-Signal Array CY8C27x43

    I am building the same using a PSoC( Programmable System on Chip). I will give a tiny snapshot from their site FYI. PSoC Mixed-Signal Array.

    I had corresponded with you some time back when you had guided me to making a temperature controller .It was a very nice experience doing the same.

    A true system-on-a-chip, PSoC devices are configurable mixed-signal arrays that integrate the microcontroller and related peripheral circuits typically found in an embedded design.

    mail from TF

    Programmable System-on-Chip - PSoC - CY8C27x43

    The PSoC family consists of many Mixed-Signal Array with On-Chip Controller devices. These devices are designed to replace multiple traditional MCU-based system components with one, low cost single-chip programmable device. PSoC devices include configurable blocks of analog and digital logic, as well as programmable interconnects.

    PSoC EvalPods

    PSoC EvalPods are pods that connect to the ICE In-Circuit Emulator (CY3215-DK kit) to allow debugging capability.

    CY3210 - CY8C27x43 PSoC(R) Evaluation Pod (EvalPod)

    They can also function as a standalone device without debugging capability. The EvalPod has a 28-pin DIP footprint on the bottom for easy connection to development kits or other hardware.

    Saturday, April 04, 2020

    Interface 89C52 with 7135

    i am interested in doing with 89C52. And now I trying to use AT89C52 and ICL 7135. And I use nterrupt 0 to get BCD data from ICL7135. I send you my program here and expect to get your advice soon.

    post by NHT



    I have made a circuit for you to study, also some idea about the code. you need to have Adobe Acrobat Reader

    You can find it here Microcontroller you can now try to write the code and draw the circuit you need.

    AT89C52 Parallel Interface to ICL7135

    AT89C52 Parallel Interface to ICL7135

    This circuit is an interface between 89C52 of Atmel with 7135 of Intersil.  With This circuit you can read analog data of both polarities you can change the range scale with extra circuits, you can store data on a EEPROM or send them to PC thru RS232 or Comm port.

    delabs


    Friday, February 21, 2020

    What is a Relay - Jim Asks

    (A text chat in Google talk long ago from my email records - 2007)

    Jim: hello,
    delabs: hello

    Jim: i have a Small problem,it's about relays.me: would u pls give me an information about relays,pls give different types of relays and their differences.

    delabs: for what do you want to use the relay for.

    What is a Relay - Jim Asks

    Jim: Two door alarm settable for close or open door

    delabs: there is a control signal and an output for relay, if you are using just a buzzer for alarm, no relay needed if you want to operate a big hooter or 230V lamp a relay is needed- or even a motor or solenoid to move some thing  Even a Solid State Relay can be used.

    Bigger loads like large motors may need drives and containers. Some even have speed control. Big doors are more difficult to open and close. safety features needed.

    The picture above shows also reed relays that are used for small signals - analog and telecom. In Solid State switching also we have small signal and power switches, using mosfet or triac.

    Soldermans Basic Electronics: Relays and Contactors

    Jim: let me check dis addr nd i'll get back 2 u just now.
    Jim: ok but if i have a problem i'll get back 2 u,bye

    Thursday, February 13, 2020

    Soldering Iron Tip

    Can I use stainless steel to replace a defective soldering iron tip?

    mail from EA

    Soldering iron tips are mostly alloys of copper. the thermal conductivity of steel is poor. buy a soldering iron tip available in the local market.

    This image has a Tip for Soldering Iron and also has Soldering Iron Tips.

    Soldering Iron Tip

    Change Weller ET Series Soldering Tips

    Changing the soldering tips on a PES51 pencil is very simple. You just have to make sure to take your time and don't force anything. Damaging your iron is not only possible, but easy when replacing the tips, so proceed with care.

    Weller tips are magnetic and only original weller tips to be used.

    The Basic Electronics Soldering & Desoldering Guide

    The Basic Soldering Guide contains everything the beginner needs to solder electronics successfully, with guidance on choosing the right soldering iron, details of various solders and fluxes,

    delabs

    Thursday, February 06, 2020

    Passive volume control

    please if you don't mind I need to help to find a control circuit for volume of speaker 4 ohm or 8 ohm located in the another room far away of cassette or CD player by using only passive components with potentiometer without transformer.

    mail from AD



    i have attached to this mail a simple circuit you can build at home at low cost. This is the only alternative for the need that you have specified. it uses just a rotary switch and wire wound resistors.

    Home Made Circuits

    Volume control circuit for speaker 4 ohm or 8 ohm located in the another room far away. by using only passive components. This gives limited control and helps reduce volume when a conversation starts. The resistors are very low value.

    Passive volume control with Potentiometer

    A simple circuit you can build at home at low cost it uses just a rotary switch and wire wound resistors. Add more resistors and a rotary switch with more contacts for finer control.

    delabs


    Monday, January 13, 2020

    Seven Segment LED display

    how is the circuit for driving a seven segment led

    mail from EA

    A 7 segment LED display is used to display a number 0-9 using 7 LEDs, The circuit you design must have a BCD output, BCD means Binary coded decimal for number 0 it is 0000 and for number 9 it is 1001 see this chart i put in my site....  Electrical Tables

    the BCD is fed to a BCD to 7 segment decoder like CD4511 or 7447 which has the logic to take care to drive your display, the displays are two types common anode and common cathode you have choose a driver to match your display, you will need to use current limiting resistors for every LED to limit current to 15mA or less. there are many circuits in my website which has examples of these.

    Seven Segment LED display

    you can also drive such displays with 7107 or 7135 to display analog signals, or with a microcontroller like 8051 using software decoding, even such examples and code is available at my website.Digital-Circuits. and Logic-Circuits.

    delabs

    I made an online tutorial for seven segment LED. Hope it helps you learn more.

    Digital up down BCD counter "Simple Digital up down counter CD4029, with interactive javascript simulation." You can run the circuit online and try out without wiring it up.

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    Winding Transformers and Coils

    i would need your help in designing transformers for rechargeable lamps. i really don't understand what the dots in front a coil stands for. all help (including pictures) would be really appreciated. my own just packed a few days ago and i would love to recoil the transformer.

    mail from LA



    You will have to do a lot of study in the internet, and experimentation too. Transformer winding is a specialized profession not a hobby at all. You can wind some coils or small signal transformers, that is ok. Please do not try to wind mains or 230/110 V transformers at home.

    Winding Transformers

    I can only give some tips, precautions and techniques to a winder. study these links....

    Electrical Formulas, Calculations, Basic Electronics Engineering
     
    I have put the link of a page but see all the pages of the website. The Dot polarity in a transformer stands for the direction of winding relative to each other. The Direction of winding could be clockwise or anti-clockwise.

    delabs


    Hi, I have a DV 4295 small Transformer (salvaged from an unknown purpose PCB)Pri: 1x220V 50Hz, Sec: 2x17.5V 2x1.5VA (2x2 pins). There is no indication on the housing about dot polarity and no datasheet could be find. How can I determine the dot polarity of the Secondaries? THX

    Mail from HF



    Transformers Series and Parallel Connections

    Series and Parallel Connections in transformers. Observe the Dot-Polarity. When windings are in parallel the current capacity doubles.

    Transformer Polarity

    An understanding of polarity is essential to correctly construct three-phase transformer banks and to properly parallel single or three-phase transformers with existing electrical systems.

    NE612 - Balanced mixer with Local Oscillator

    I am designing a circuit that implements an AM radio circuit that ultilises the IC Double mixer and Oscillator NE612. I was just wondering whether there is any standard symbol for this kind of IC.

    mail from CM


    There is no standard symbol for NE612, just a square box. You have to make a custom part in the CAD software or see if someone has done that. check these links on info of NE612 circuit and symbol....


    GM47: Simple 30m Band QRP CW-Transceive 

    The Rx mixer is followed by a IF stage featuring an NE592. The mixer's balanced output is directly connected to the amplifier's differential input, minimizing component count at this point.

    Direct Conversion Receiver using NE612 for HF Bands

    The NE612 is an integrated circuit which contains a balanced mixer with its own on-board local oscillator and voltage regulator. The mixer can provide up to 18dB of gain at 45 Mhz, and the local oscillator will operate up to 200 Mhz.

    NE612 - Balanced mixer with Local Oscillator

    HF Transceiver using NE612

     I would be working on the Transverter first, as with this, I could try out the 9Mhz SSB Module that I already have. I would be building the Transverter for the 14 Mhz band depending on the values from my DC Receiver project using the NE612 IC
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