Whenever I use the 555 timer, it seems that the output polarity is invariably incorrect, and the way the 555 functions, it normally cannot generate a duty cycle of less than 50% — 90% yes, 10% NO!

The venerable 555-type timer makes an effective driver for power MOSFETs, but you have to understand the drive situation when selecting the correct variation of the basic timer. This idea shows how ...

The circuit was designed without the use of a power supply or a moving coil voltmeter to create a quick battery tester which can test 1.5 V to 15 V battery cells with a two-LED display. BC337 – a ...