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Monday, October 12, 2020

Up-Down counter-timer

(A question answer thread of, 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?


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.


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


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


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


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


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. 


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. 


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.


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 -

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


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)


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.