AC voltage probe (CB8185E)

This circuit for voltages up to about 20 V was found in a 90s Popular Electronics. The LED can be of any type or color.

Mechanical Reverberator (CB23995E)
This mechanical reverberator circuit for guitar was found in the February 1970 issue of Radio...
Pulse Generator (CB19332E)
This circuit generates high pulses from a sinusoidal input, using SCRs for this purpose. The...
VLMU3510 365 130 High Power Ultraviolet LED (COM118E)
September 2016 - It can be purchased from Mouser Electronics the new ultraviolet high power LEDs...