This circuit for incandescent lamps was found in the February 1972 Radio Electronics magazine. The triac is rated according to the lamp power and the sensitivity adjustment is made in R1.
To operate in a harmonic of the crystal frequency, tuned to a trimmer in the resonant circuit of...
This amplifier for recording heads was found in a Radio Electronics from September 1963. The...
This circuit is from the 1983 Intersil Databook. The circuit operates on 5 V power and has a...