We found this circuit in a 1985 technical publication. The circuit uses PUTs to drive lamps. Relays or LEDs can be used with the voltage according to the supply.
Today we have more compact solutions. This is from a Radio Electronics magazine from October 1990....
This filter was found in Texas Instruments documentation from the 1980s. The circuit uses a common...
16 commercial test circuit for tubes and transistors appeared in Radio Electronics magazine in...