This simple 15 V power supply was found in an article describing an assembly in the January 1987 Radio Electronics magazine. The power supply is used to power the circuit described.
This circuit makes use of an operational amplifier from the 80's. The circuit can be implemented with...
When the power is cut off, this circuit keeps the flashlight on for a while, allowing it to be...
Using the CK722 this directional photometer was published in Radio Electronics magazine in July...