Transistor-Transistor TTL Logic and Totem pole output

Started by Patrick Chung in sci.electronics.basics3 years ago

By combining basic TTL Logic NAND gate with invertors and other gate any logical function can be realized in TTL technology. TTL family of logic...

By combining basic TTL Logic NAND gate with invertors and other gate any logical function can be realized in TTL technology. TTL family of logic circuits is specially empowered with TTL Totem pole output Read more: http://www.cirvirlab.com/index.php/electronic/181-transistor-transistor-ttl-logic.html


TTL input circuit to drive diode

Started by Gary H in sci.electronics.basics11 years ago 5 replies

Hi. I need a little help with something that should be pretty basic. I have a control board that has a TTL output to turn on and off a laser. ...

Hi. I need a little help with something that should be pretty basic. I have a control board that has a TTL output to turn on and off a laser. The laser is nothing more than a diode that consumes about 60mA. So, I want to be able to turn the diode on or off with the TTL output. I don't really know much about TTL requirements. But, would a NPN transistor with resistor between the bas...


MOSFETs and PWM

Started by Randy Day in sci.electronics.basics11 years ago 41 replies

I've built some TTL motor/relay controllers out of NPN transistors in a Darlington configuration, and I'm considering using mosfets instead. ...

I've built some TTL motor/relay controllers out of NPN transistors in a Darlington configuration, and I'm considering using mosfets instead. +V |_ - )| ^ )| relay |_)| | _R_ |/ TTL in -|___|--| |> | GND (cre


pulse counter

Started by George Herold in sci.electronics.basics8 years ago 10 replies
TTL

I want to count TTL pulses from a PMT. (There is already some pulse shaping and discriminator electronics between the PMT and output.) The TTL...

I want to count TTL pulses from a PMT. (There is already some pulse shaping and discriminator electronics between the PMT and output.) The TTL pulses have a fixed width of 300ns and a rate from 10 Hz to several hundred kHz (coming at random times). In the good-old-days all the frequency counters did this just fine. You selected a gate time and the thing just counted the number of transitio...


Serial Breakout Box

Started by Rolf in sci.electronics.basics3 years ago 3 replies

Looking for an inexpensive (less that $100) serial RS232 breakout box. Can set BAUD, etc and then receive serial data. needs to have some sort...

Looking for an inexpensive (less that $100) serial RS232 breakout box. Can set BAUD, etc and then receive serial data. needs to have some sort of data bit output; TTL or ?. up to 8 bits. nice to be able to send simple data byte back. A kit is fine. what's out there? I already have USB breakout boxes so that is not needed. --- news://freenews.netfront.net/ - complaints: news@netfr...


555 timer question: how to calculate required resistors and capacitor to achieve desired frequency?

Started by Impmon in sci.electronics.basics11 years ago 14 replies
TTL

I tried Googling but all the formula for finding 555 timer frequency is based on known capacitor and resistor values to find frequency. I need...

I tried Googling but all the formula for finding 555 timer frequency is based on known capacitor and resistor values to find frequency. I need to build a monostable timer to get 140Hz. I could throw in a random capacitor and one resistor but my algebra skill is rusty (no complex math formula in over 10 years!!) The system will be running on 5v DC as it contains a few TTL chips. -- Whe...