This car battery monitor was featured in the January 1988 issue of Radio Electronics magazine. The circuit uses common transistors and has 3 levels of indication made with common LEDs.
This well-designed phase shift oscillator configuration was found in ancient European...
A stereo digital mixer using the 4053 is built as shown in figure bellow. The IC must be powered...
The resistors R determine the frequencies of the oscillator together with C. The circuit is from a...