Hello all
I'm trying to put together a low power 555 monostable circuit and have come up with the following design, having modified the circuit from this source. http://www.instructables.com/id/555-Timer/?ALLSTEPS
My thinking was that once the main switch is pressed and power is applied to the circuit, the trigger pin will detect a low signal causing the output to go high; this should supply a signal to the transistor allowing power to remain supplied to the circuit even once the main switch is off but only until the timer has run its course at which point it will switch off leaving the whole circuit in a state where it isn't drawing any power.
However trying it out on prototyping board isn't giving much success, can anyone suggest what i've done wrong or perhaps a good alternative circuit to achieve the same task?
Cheers
Oddy
p.s. the threshold capacitor is a 220uf and there is a small decoupling type capacitor on pin 5.
I'm trying to put together a low power 555 monostable circuit and have come up with the following design, having modified the circuit from this source. http://www.instructables.com/id/555-Timer/?ALLSTEPS
My thinking was that once the main switch is pressed and power is applied to the circuit, the trigger pin will detect a low signal causing the output to go high; this should supply a signal to the transistor allowing power to remain supplied to the circuit even once the main switch is off but only until the timer has run its course at which point it will switch off leaving the whole circuit in a state where it isn't drawing any power.
However trying it out on prototyping board isn't giving much success, can anyone suggest what i've done wrong or perhaps a good alternative circuit to achieve the same task?
Cheers
Oddy
p.s. the threshold capacitor is a 220uf and there is a small decoupling type capacitor on pin 5.