Re: programmable circuit breaker

Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:

john larkin <jl@650pot.com> wrote:
 
[...]

Maybe I shouldn't diode clamp the relay coils. I'll have to test the
dropout time.

 
Put a resistor in series with the clamp diode, the value can be chosen
to keep the inductive spike just below the maximum allowable voltage and
that will give the fastest turn-off.  By using higher voltage switching
transistors you can have a higher voltage spike and a faster turn-off -
but there is the risk that the spike might be capacitively coupled to
somewhere vulnerable to damage.
 
 

Or even just a resistor and no diode! The extra few percent current
consumption is often not a problem and a resistor is very reliable, more
durable than a diode.

--
piglet