This is one of the many versions of this type of indicator that the reader can find on our website. This is from Mullard's 1969 documentation. The indicator is 95 uA (100 uA).
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...
This configuration, widely used in our articles and on this website, uses a 555 to control a relay...
This circuit was found in an English documentation from the 90s. It uses a PLL CMOS 4046 and is...