This battery-powered micropower supply was shown in Radio Electronics magazine in 1991. The maximum current is 170 mA. and the integrated circuit is the MAX655 from Maxim.
This 1960s Signalite circuit uses two SCRs to achieve full wave control. The trigger elements are...
This circuit is from a Popular Electronics from the 90's. The circuit activates a buzzer with...
Pressing and releasing S, the capacitor C1 charges and discharge slowly through the oscillator...