Showing posts with label Transistors. Show all posts
Showing posts with label Transistors. Show all posts

Tuesday, July 12, 2016

Ultra Sound Sender Detecter Diagram

I am a University Physics technical staff member and I am searching a Diagram and full detals about Ultra sound detecter (Sender & receiver & Detecter). It must be arround (Detecting range ) 1.2 MHz. This is for the student practical activities.

Pl help me if you have any information. This will be a gratefull help to the students for their studings.

Mail from PBG Sri Lanka

See an earlier post - Ultrasonic distance measurement if i find more it will be added here Ultrasound Have a look at all links below, that might help

Ultrasonic Sound

"Sounds in the range 20-100kHz are commonly used for communication and navigation by bats, dolphins, and some other species. Much higher frequencies, in the range 1-20 MHz, are used for medical ultrasound."

Ultra Sound Sensor

4QD-TEC: Ultrasonics: remote control and Intruder detector - These ultrasonic circuits are all quite old: my notes date them at mid-70s so ... The last circuit is an ultrasonic preamp with a twin T feedback to make it ...

Schematics Depot (tm) - ultrasonic switch circuit - The ultrasonic receiver circuit uses an ultrasonic receiver transducer to sense ultrasonic signals. It also uses a two-stage amplifier, a rectifier stage, ...

Silicon Chip Online - Circuit Notebook - Besides being used as a Bat Detector, the circuit could also be used as a simple tool to indicate frequency, to find tyre punctures (which emit ultrasound), ...

Ultrasonic (Ultrasound) Electronic Circuits - Ultrasonic (Ultrasound) Circuits


Thursday, July 07, 2016

Understanding Transistor Power Dissipation

I like your page about current source circuit basic design. However, I still have Little confuse of the power dissipation calculation.

The max power dissipation of my circuit is 20.5V x 0.5A = 10.25W, but transistors I found are 2W power dissipation. But my input voltages is just varied from 18.0V to 20.5V only. Do you think the 2W power dissipation transistor is fine? Any help will be appreciated.

Mail From MT

When the Current source output is short circuited or connected to a low impedance load say 10 ohms, the full voltage of input 20V falls across the transistor but current is limited to 0.5A. which means the 2W transistor may Roast. The transistor when conducting, the watts is the volts across it and current thru it. Not your supply Voltage.

Power Electronics & Solar Energy

HeatSinks in Electronics

HeatSinks in Electronics - For all types of packages, there are heatsinks. They are mainly made of Black Anodized Aluminium. Aluminium is a good conductor of heat and Anodizing prevents any form of corrosion. Linear Regulated Supplies, RF Transmitters and Power Amplifiers have Devices that need heatsinks. Use Mica, Silpad, PolySulphone Pads for Electrical Isolation. HeatSink compound too.

Power Supplies Section

Design in such a way there is no short circuit or a a power resistor in source. But then efficiency drops. The best way is to use a switching supply design or keep the input voltage across transistor to a minimum.


Saturday, May 16, 2015

Power Supply Regulators and MOSFET Transistor

HELLO THERE ...COULD anybody pls help me with a place to get more information on the following components...cant seem to find it anywhere.

W20NB50 W8NB100 found them in a liteon power supply pack for a database supply. i just don't know what they stand for. ...saw on a web page that it is produced by ST micro electronics. i went there but no show ..can somebody pls help?

post by FP

W20NB50 ST Power MOSFET Transistors TO-247 N-Ch 500 Volt 20 Amp
W8NB100 ST Power MOSFET Transistors TO-247 N-Ch 1000 Volt 8 Amp

You  will find equivalents here - NTE Electronics - N-Channel MOSFET Selector

ST’s MOSFETs with a breakdown voltage > 650 V offer low gate charge and low on-resistance down to 0.275 Ω (850 V) in PowerFLAT 8x8 HV packages.

Junction design of a Mosfet

Junction design of a Mosfet

"The source-to-body and drain-to-body junctions are the object of much attention because of three major factors: their design affects the current-voltage (I-V) characteristics of the device, lowering output resistance, and also the speed of the device through the loading effect of the junction capacitances, and finally, the component of stand-by power dissipation due to junction leakage."

Updated - July 2013


Sunday, April 19, 2015

What is Saturation in Transistors

Date 8/30/06 Simon and delabs
Simon: hello,anantha.
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 anan
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,

This concludes this episode of Saturated Talk with Simple Simon. Next week, a new Episode which will cover effects of Lightning Bolts.

To learn more about Saturation in NPN and PNP Devices see - Transistors Williamson Labs

Transistor Operation - A transistor in a circuit will be in one of three conditions

Chapter 5: Bipolar Junction Transistors

"Saturation also implies that a large amount of minority carrier charge is accumulated in the base region. As a transistor is switched from saturation to cut-off, this charge initially remains in the base and a collector current will remain until this charge is removed by recombination."

Lessons In Electric Circuits - Bipolar Transistors
When a transistor has maximum current through it, it is said to be in a state of saturation (fully conducting).

Wednesday, November 19, 2014

Electronic Fifteen LED Roulette

The following was submitted on July 11th, 2007 at 12:47AM (PDT). 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.

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

Electronic LED Roulette

See these circuits you will get an idea, Using CD4514 is also possible.

555 and CD4017 Running Lights