Based on NXP 74HC logic, this circuit can be adapted for various uses. The circuit can also be used with 12V power, and the circuit replaced with a common 4046 PLL.
This circuit of a 1978 American publication monitors a telephone line by triggering a relay. The...
When S1 is in 1, the circuit operates with of half the total power applied to the load. When in...
This power supply also has a fine adjustment feature. The transformer is 16 + 16 V with 3 A and...