This circuit was suggested by Motorola in a 1980s publication. It is based on a PUT that is not a common component today. The division depends on the capacitor values according to the table.
This circuit sensor is an NTC with a resistance of the order of 2k. The SCR can be from the TIC...
The load current can be adjusted up to about 1 A. The transistor can be TIP32 or TIP42. The...
This oscillator with common general-purpose transistors appeared in Radio Electronics magazine in...