This balance indicator for stereo amplifiers was found in an 80's Elektor. The components used are common. Zeners are 1.8 V or close to that value.
The integrated circuit used is equivalent to the 555 and the transistor can be the BC558. R1 and...
This configuration, which appears in the manual of other manufacturers, is an excellent 1.5 V...
This simple timer based on unijunction and SCR transistors is from 1995 documentation. The maximum...