The configuration shown allows to obtain a high voltage gain for FETs. FETs can be BF245 or MPF102. The circuit is from the 1977 National Semiconductor FET Databook.
The figure shows how to control the blinking of a 5 V blinking LED with an LDR. The LED only...
Suggested by Maxim in documentation from the 90s, this circuit has its response curve given next to...
This circuit is from a 1965 General Electric publication. It uses a thermistor to fire a reed...