The sensor of this circuit is a photodiode. Equivalent operations can be used, and the instrument can be replaced by the lower current range of a standard multimeter.
This circuit appears on this site from different sources. This is from documentation from the...
The circuit shown in the figure consists of a low voltage drop (LDO) regulator for 200 mA using the...
The operating principle of the VCO shown in the figure is the same as the CIR4598 circuit. The...