This is the circuit for the HM-10ª, an instrument sold by Heathkit. The circuit is from a Radio Electronics from May 1963. The indication is by an analog instrument.
This is one of the many versions of this type of indicator that the reader can find on our...
This circuit is from a manual of linear integrated circuits of the 80s. The operational is of the...
This circuit has a 100 dB dynamic We found it in a Popular Electronics from the 90s. Equivalent...