Re: One shot timer
That's quite cunning! And good because once it 'trips' the mains is removed from the supply-side of whatever you're powering.
I did have something similar a while back - a NiCd battery-charger with a charge-timer where the mains supply came through a relay. You put the batteries-needing-charging in the thing then pressed the 'start' button which briefly connected the batteries to the relay-coil which pulled-in applying mains and starting the countdown-timer as well as latching the relay. When charge was complete the timer de-energised the relay, cutting off the mains.
I forget who made this but I liked it because once the batteries were charged the mains was removed from the charger primary-side, unlike a lot of cheaper NiCd chargers where the priomary remains powered when the charge-cycle is complete.
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