This circuit was found in an American documentation from the 1980s. The sensitivity ranges from 100 mV to 1 V. The supply must be done with an excellent filtering source.
We find this circuit in a 1970 publication. Transistors can be replaced by current equivalents and LDR is...
Featuring low output impedance and high input impedance, this configuration was found in a 1980s...
Found in a 1980s American documentation, this circuit can use a SCR and a general-purpose transistor....