This PUT circuit was found in a 1967 General Electric SCR manual. The basic component is unusual, and the capacitor must be low-leakage.
This circuit for the 1.5 to 15 V scaled ranges was found in a 1982 documentation, but uses current...
In this circuit the relay triggers on when light falls onto the sensor, a common LDR. Power supply...
The modified Hartley oscillator seen in the figure can generate signals ranging from 3 MHz to 10...