What would be a circuit design that would produce a momentary (low voltage DC) pulse, rather than a continuous low voltage current, from a phone charger (already plugged into a 240 volt mains power socket) when the mains socket switch turns the phone charger on?
I’m a novice when it comes to designing even a simple electronic circuit so I need your help to solve this puzzle which, hopefully, is all too obvious to your experienced eye!
When the mains switch is turned on the phone charger will, of course, produce a constant 5 volt direct current, but I want only a momentary 5 volt pulse. This is pulse would trigger the operation of a simple 555 timer delay circuit so that it can do its job of turning off a lamp after a set period of time: a continuous 5 volt current from the phone charger will, of course, defeat the efforts of the timer circuit to switch the lamp off. The low voltage DC pulse is intended to replace the action of the “push-to-make” button switch that currently triggers the timer circuit and the power for the timer circuit is supplied only when the mains AC power socket is turned on and left in the “on” state.
I hope this gives enough information to clarify my objective and your comments and ideas will be appreciated.
Many thanks.
I’m a novice when it comes to designing even a simple electronic circuit so I need your help to solve this puzzle which, hopefully, is all too obvious to your experienced eye!
When the mains switch is turned on the phone charger will, of course, produce a constant 5 volt direct current, but I want only a momentary 5 volt pulse. This is pulse would trigger the operation of a simple 555 timer delay circuit so that it can do its job of turning off a lamp after a set period of time: a continuous 5 volt current from the phone charger will, of course, defeat the efforts of the timer circuit to switch the lamp off. The low voltage DC pulse is intended to replace the action of the “push-to-make” button switch that currently triggers the timer circuit and the power for the timer circuit is supplied only when the mains AC power socket is turned on and left in the “on” state.
I hope this gives enough information to clarify my objective and your comments and ideas will be appreciated.
Many thanks.