- on Miscellaneous Electronics
- Published in issue 7/2010 on page 42
(Summer Circuits 2010 article)
This voltage monitor circuit is based on an Elektor design with a 555 timer IC in the book 302 Circuits, which uses two LEDs (red and green) to indicate whether the voltage is within range (bad or good). However, in practice this circuit has some shortcomings because the change in the indicated colour when the voltage drops below the threshold often goes unnoticed.