This circuit generates a siren sound. It was found in the April 1969 Radio Electronics magazine. The output signal is to be applied to an external amplifier.
This circuit was taken from the 1974 Ferranti transistor manual. Transistors are common types at...
This circuit monitors the current of a series of 40 V lithium battery packs connected in series....
This 1970 Philips circuit uses a mechanical counter. The circuit is triggered by a reed switch...