That is all good information but not quite what I’m looking for. What I want is: a pulse to latch the relay up (power on, then off), then a while later, say ½ hr, another pulse to un-latch the relay.
These designs show the relay latching when the power is applied and un-latching when the power is removed ie
Set
When a specified voltage is applied
across E, the current flows through the
circuit in the sequence of diode Di1,
capacitor C, relay Ry, and diode Di2.
C is then charged, setting the relay.
Reset
When the voltage placed across E is
removed, the electricity charged in C is
discharged, causing the current to flow
through the circuit in the sequence of Rb,
the base, and the emitter of TR. In this
way, the relay is reset by the current
flowing in the direction opposite to when
the relay is set.
What I am looking for is when the voltage is applied and removed, the relay is latched up, when the voltage is applied and removed again, the relay is un-latched.
I’m not very knowledgeable about this stuff, just enough to be dangerous.
Maybe I won’t be able to get it to work the way I want.
Anyway, thanks for all your help.
Neil