Relay switches

[Tony Allgood]

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

This is true. But you do have two options:

1) Use a bistable relay. Yes, they are available from various
manufacturers.

2) Use a normal relay, whack the relay with its full amount to turn it
on, but then reduce the drive current/voltage to the hold amount. This
is normally given in relay data sheets. You can reduce the current to a
tenth or less of the trigger amount. This can be done crudely, with a
capacitor, or by some other more refined means. Data sheets from relay
manufacturers give out this sort of information. There are some relays
with sort of thing built in. Matsushita make some very good relays. I
think they used to be called SDS-Relais in my day.

Regards,

Tony Allgood  Penrith, Cumbria, UK

Walsh synthesiser, SuperLadder, TB303 clone and rack mounted filter

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