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).
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
The integrated circuit of this amplifier is not very common today. The output transistors can be...
Found in an old documentation about neon lamps, this circuit has the frequency basically...