Help me! I'm very need to your help, design traffic light with IC

MrAl

Joined Jun 17, 2014
11,496
Just a little post thread note...

It is easy to create an oscillator from either two 2 input nor gates or two 2 input nand gates, and a capacitor or two and maybe a resistor. These have been around as long back as i can remember, 1972 or probably before that. The only trick is picking the right capacitor value(s) that get it to work without stressing the gate outputs too much yet still be able to drive the inputs and get to the right frequency as well. If you have to use a smaller capacitor than you really would like to, then you have to include a divider circuit to divide down the frequency until you get to the required frequency. My first frequency generator board used this idea, but i used a crystal instead of a capacitor for the timing and an additional coupling capacitor, then divided the signal down to 1/2 Hz with binary and divide by 10 chips. Got lots of different frequencies that way out of the various stages of the divide chips. Started with a 2MHz crystal but you can go lower or higher as needed as long as the first divider chips can operate at the required frequency.
The board was about 6 by 8 inches custom etched for experimental circuits. I still have it maybe i'll take a pic. That was back around 1975 ha ha when standard TTL was still being used a lot for a lot of things. I might have upgraded to the LS series later cant remember offhand been years since i needed it.
 

Thread Starter

mickeykhuongtran112

Joined Nov 25, 2021
11
post threa
Just a little post thread note...

It is easy to create an oscillator from either two 2 input nor gates or two 2 input nand gates, and a capacitor or two and maybe a resistor. These have been around as long back as i can remember, 1972 or probably before that. The only trick is picking the right capacitor value(s) that get it to work without stressing the gate outputs too much. If you have to use smaller capacitor than you really would like to, then you have to include a divider circuit to divide down the frequency until you get to the required frequency. My first frequency gnerator board used this idea, but i used a crystal instead of a capacitor for the timing and an addition coupling capacitor, then divided the signal down to 1/2 Hz with binary and divide by 10 chips. Got lots of different frequencies that way out of the various stages of the divide chips. Started with a 2MHz crystal but you can go lower or higher as needed as long as the first divider chips can operate at the required frequency.
The board was about 8 by 8 inches custom etched. I still have it maybe i'll take a pic. That was back around 1975 ha ha when standard TTL was still being used a lot for a lot of things.
Thanks for your contribution! Looking forward to the details for this way!
 
Top