This circuit for UHF between 800 and 1 000 MHz was found in an American documentation from the 90's. The integrated circuit is from that time, uncommon today.
This simple circuit causes an LED to light up when the battery voltage drops below the voltage set in the...
Obtained from a 1967 documentation, this circuit uses transistors from the time. The galvanometer can be a...
The figure shows how to implement an alarm buzzer in an LM3914 to warn about crossing the scale...