This is the application note circuit of the integrated circuit used with the LASER diode. The circuit was obtained from the Electronics Experimenter's Handbook of 1992.
This circuit appears elsewhere on this site, but from different sources. Using the LM3900, we find this...
This interesting source or isolation transformer also allows to vary the output voltage by...
In this circuit the CA3140, an operational amplifier, is used as a comparator with the zener diode...