Externet
Well-Known Member
Hi.
From a 120VAC or 240VAC source, with no transformer, I want to rectify it and slowly charge a capacitor that at certain level will discharge by driving with a pulse of not more than one second once a minute to a LED or buzzer or both.
In other words, when AC is present, be warned it is on. No batteries involved.
Like the opposite of a smoke alarm that chirps when its battery is low : To chirp when is on.
Is there such thing in the market ? Perhaps some gadget works like that ? Would be extraordinary if fits in an AC plug if is not asking too much. As to plug it in an outlet and be reminded it is on.
From a 120VAC or 240VAC source, with no transformer, I want to rectify it and slowly charge a capacitor that at certain level will discharge by driving with a pulse of not more than one second once a minute to a LED or buzzer or both.
In other words, when AC is present, be warned it is on. No batteries involved.
Like the opposite of a smoke alarm that chirps when its battery is low : To chirp when is on.
Is there such thing in the market ? Perhaps some gadget works like that ? Would be extraordinary if fits in an AC plug if is not asking too much. As to plug it in an outlet and be reminded it is on.