This detector uses an unusual sensor today. The circuit is from an 80s documentation. Its sensitivity is 10 ppm. The transformer has two secondary voltages.
This circuit is the conventional use of the 7805 as a constant current source up to 1 A. The...
We found this circuit in a 90s Radio Electronics. The integrated circuit used is uncommon today. The...
This amplifier can be used for public-address or other applications. Three transistors of the time...