I have looked through the posts but may have missed one if similar to my problem.
I have 12v - 13.4v from the automotive supply. I would like to have a latching TTL or some device to always start in the same state on the outputs.
The latch needs to change state based on a momentary DPDT center off contact closure from a mechanical switch. I am assuming there will be some bounce on the inputs given it is mechanical. I want to keep the circuit as simple as possible.
The questions are:
Robert
I have 12v - 13.4v from the automotive supply. I would like to have a latching TTL or some device to always start in the same state on the outputs.
The latch needs to change state based on a momentary DPDT center off contact closure from a mechanical switch. I am assuming there will be some bounce on the inputs given it is mechanical. I want to keep the circuit as simple as possible.
The questions are:
- should I try to use a simple zener and resister as a voltage source to bring the 12v down to 5v inorder to use 5v TTL?
- Or would even a resistor divider be enough given the low amount of power of the IC?
- should I use 5v TTL or would another 12v part be better and not deal with the 12v supply to 5v at all? Can someone recommend a part if so?
- would a capacitor across the outputs of the momentary switch and inputs of the latch be sufficient to stop the bounce detection if so what would be a good value? Do I also need a resistor?
- What I am trying to do is register the state of a double pole momentary switch. If pushed down one LED will light, if pushed UP a different LED will light. I am assuming that there will be two inputs to the latch to drive the output opposite to each other and that the latch will stay until the alternate push is detected.
- The latch has to start in the same state from power up of the supply (in case the battery is disconnected).
Robert