Using a 4-layer diode, an unusual component today, this circuit was found in an American documentation from 1964. The circuit can be tested using a diac.
This circuit was found in 80's Popular Electronics. The components used are common and the number of...
September 2017 - Digi International's SX 868 RF modules for low-power 868 MHz CE / RED operation...
This circuit causes one LED to light up if the voltage falls below the value set in R3 and the...