This circuit for AC loads was found in February 1976, Radio Electronics magazine. The triac is common, and the times are given by the 20 MΩ resistor and the 1 uF capacitor.
The frequency of this Pierce oscillator, found in 1969 documentation, depends on the crystal. The...
This simple timer with unijunction transistor was found in an old American technical...
Found in documentation from the 1960s, this power supply employs germanium diodes from the time....