We found this configuration in a 1974 publication. Transistors can be replaced with equivalents such as 2N2222. The circuit has a dynamic range of 60 dB.
The circuit presented was found in a 1964 documentation. The relay can be 6 or 12 V depending on...
This IR light sensor circuit was found in the July 1992 issue of Radio Electronics magazine. It is...
This circuit is used to monitor the mains voltage, in the case of 220 V. We found it in an old...