Relay switches

[Martin Czech]

:::I need some advice on making small relay switch (12V),
:::I know of basics but if anyone messed with this things,
:::can you tell me of some good designs, I need it in pedal 
:::effect. Instead that DPDT stomp switch, I want to use
:::taster to switch some flip-flop and relay.
:::Thanks!
:::

I suppose you want a toggle switch.  Therefore you would need a toggle
FF and a reed relay, they are very small (some look like a DIP), and
very reliable. If you want a defined state @ power on, you also need a
PON reset circuitry.

A function generator I build uses toggle FF for all settings, but they
tryed to avoid debouncing RS-FF with some capacitor circuit.  This works
somehow, but not always. Debouncing is a must.

Some CD40xx circuits come as single gates in SMD packages.

I think this could be build in a very small volume.

But: such a relay needs current (~10mA) for the "on" position.  This is
not so good for battery powered applications.

There are bistable relays which toggle mechanically if a current pulse
arrives. But so far I have not seen such a device for lower voltages
and low volume. They are often made for power applications, quite large.
You know, the type of device to turn on the staircase light for all floors...

Maybe there are low voltage versions.

So, for low power, better use a CMOS switch CD 40xx or better.
Lowest power: real toggle switch.
Low power & floating potential: mechanical toggle relay.

m.c.