This circuit is from a 1968 Electronics World. It acts directly on a high voltage alternating current relay. The sensor can be a common LDR.
This oscillator has the output sine waveforms stabilized by a MOSFET. Equivalent types can be...
We found this synchrodyne receiver for the medium or short-wave band in the Radio Electronics...
This amplifier is suggested by Sanyo, for radio and recorder applications and makes use of a...