Can someone come up with a circuit that will toggle a relay using a single
The switch does have two normally open poles.
I would like to limit the circuit to a minimal number of relays and I do
have dual coil mechanical latching relay(SET/RESET) if necessary.
The relay will drive a lighting ciruit.
Push the button once and light will come on. Push the button again the
light will go off.
Holding the button will not cause the relays to chase each other. I do have
inline Artison on-delay timers if necessary, to give a 1 second delay.
It seemed simple when I thought of the idea. (it probably is but I'm
On Thu, 2 Dec 2004 19:29:13 -0700, noone put forth the notion that...
Making the relay latch on is easy. All you need to do is run power for
the coil through one of the N.O. contacts on the relay, and parallel
your momentary N.O. switch with the N.O. relay contacts. Use the other
set of contacts on the relay to control your load. You'll need a
momentary contact N.C. switch in series with the coil to turn the
circuit back off again.
I have a bunch of lights around here on circuits like this. Use a 4013 CMOS
(dual D flip flop) chip for the ON/OFF and an SSR for the A/C side. You can
have as many switches as you like.
I debounce the switch with an R/C network but there are lots of ways to do
that. At 5vdc you can drive the SSR directly.
You have indentified the problem that "chasing" will easily
happen. The way to avoid this is to use edge triggering,
rather than level sensing.
Charging capacitors up and "firing" them into relays with
latching contacts is one way. You could maybe use your
Artison timers in such a mode (I am not familiar with them -
give me some more details and I will have a thunk about it.)
Much easier, and my favourite, is to use thyristors - which
automatically latch on DC. Arrange the circuitry so that the
switch fires alternately the main thyristor and another. The
other is connected to a commutating capacitor that removes
the main thyristor current momentarily, allowing it to turn
off. The commutating capacitor only charges when the main
thyristor is on, thus setting the de-bounce time constant.
With an AC supply, you will have to stick the switching
circuit across a full-wave bridge rectifier, connected in
series with the load and supply.
An Impulse Relay is standard in many European countries for multiple
switched lighting circuits using momentary push switches. An Impulse
Relay toggles state each time it is operated. We don't normally use
Impulse Relays here in the UK though.
In logic terms, what you're after is a divide by two counter (plus
key debounce, etc).
041202 2129 - noone posted:
I installed a low voltage switching system in a large house that I had a few
years back and used a ratchet type relay. Pulse it once and it ratchets on,
and pulse it again and it ratchets off. It used just two control wires, and
was rated for 20 amps; 24 volt control. I made a pulse control circuit
board that produced a DC pulse of around 36 volts and then quickly decayed.
This would eliminate double pulsing in case a push button happened to make
double contact on one push. I used the round,white doorbell push buttons in
single gang stainless steel plates around the house. One of the plates,
which controlled some outside lights, and kitchen, entry, and basement
lights, was a single gang with six buttons in it. The kids had a time
trying to remember which button worked which light. The higher buttons
worked the high outside lights, and lower buttons worked the basement
lights. The central buttons worked the kitchen and landing lights. Easy.
In the master bedroom and kitchen I had a one gang plate with one button and
a selector switch to select the relay and the button to engage it, mostly
for outside lights for security purposes. I had a panel made at a local tin
shop and used aluminum angle and punched holes in it and placed rubber
grommets to set the relays into. This separated the high voltage from the
low voltage in the panel. I used 22 guage paired wiring -- brown/tan -- and
had no problem with voltage drop. One run was around two hundred feet of
wire out to the garage to work an outside light. The 36 volt DC pulse
wasn't on the wire long enough to create a problem, and the relay, which was
in the garage in a separate box pulsed on and off as demanded.
I thought it was a neat system. It worked really well. It was safe, and
there was no maintenance to it.
Thanks for the input. My answer was found with the relay below. An impulse
I had the circuit down to a basic set/reset latching relays with on delay
timers to debounce the switch.
This made it a lot easier.