This circuit is from a 1965 General Electric manual. It uses components from the time that admit equivalents. The SCR can be the TIC106 and the LDR of any type.
Mouser Electronics owns the Littelfuse SP3422 low-capacitance TVS diode arrays. These components are...
This variable oscillator with crystal was found in a Popular Electronics of the 90s. The circuit uses...
This high quality circuit with complementary symmetry was found in an Electronics World of 1966....