Using an operational amplifier, this circuit from a 90s Popular Electronics, is characterized by its high sensitivity. R5 can be added to control the gain.
This common emitter amplifier with 43 dB gain was found in the August 1970 issue of Radio...
This circuit was found in a technical documentation from Texas Instruments, using a...
We found this circuit in a 1980 publication. It can be applied to Triacs of the TIC series and the...