Hey gang,
I would like to get ttl logic to toggle back and forth from high to low by pushing on a momentary contact pushbutton.
any suggestions for a circuit?
Owen
Hey gang,
I would like to get ttl logic to toggle back and forth from high to low by pushing on a momentary contact pushbutton.
any suggestions for a circuit?
Owen
Do you mean you want a logic level oscillator to start on the pulsh of a button?
Phil
Owen, Do you have a 7474? If I recall from my ttl days wire the PB to the Clock, connect /Q (Q bar out) back to the D input and use the Q output. If I remember correctly this will toggle the output every pulse.
I will have to dig out my old notes, unless someone has a better idea.
Al
BTW tie the clear and set high for normal operation.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Phil, not an oscillator per se. I want to poke a momentary contact switch and have it send a circuit to high and have that circuit stay high. Then I'd like it to send the circuit to lo when it gets pushed again.Originally posted by pminmo
Do you mean you want a logic level oscillator to start on the pulsh of a button?
Phil
So far I've wired a 555 timer to debounce a push button switch, and now I'm looking for it to flip-flop a ttl circuit.
owen
one more question, is the push button double throw? i.e. has normally open and normally closed contacs? The reason I ask is if it has both contacts you can do the dbounce with one half a flip flop.
Phil
single pole.Originally posted by pminmo
one more question, is the push button double throw? i.e. has normally open and normally closed contacs? The reason I ask is if it has both contacts you can do the dbounce with one half a flip flop.
Phil
This one has worked for me, it has a 7404 debounce circuit into the 7474 dual D flip-flop.
Al
Oops I hope I can make the File a bit bigger!
Hoo boy.
I'm laughing out loud here because I'm really anxious to get a circuit and I clicked on yours and got this unreadable picture.
Al, could you be kind enough to try to post again, or just send it to [email protected]
thank much :-)
owen
I'm glad to see someone still does it this way.
Give the problem to a student today, and there is a good chance he would come up with a PC Pentium4 3GHz w. 1GB RAM and a VB program to solve your problem. :-)
Al,
just to follow up, the circuit worked great. I went with using a 555 for the debouncing part because that's what I had on hand. The circuit is included here...
owen
Owen, Glad it worked, I date back to when we had to do this at one time with discrete components, that was a challenge!. Hail the IC.
Al
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Al,
I think maybe we were separated at birth.
remember when it wasnt possible to go to the net and get a data sheet on chip?
because there wasnt a net...
or computers...
or chips. :-)
owen
dunno, looks too hitech to me
maybe...
yeah I saw that one on the net. I couldnt go with the transistor approach because I'm only operating at 5 volt levels. good to include here if anyone searching this site later on.
owen