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.
We show in the figure how to implement the No-AND or NAND logic function using a general-purpose transistor....
This circuit was found in a 1980s documentation. Modern general purpose transistors can be used....
Many collectors of records, tapes and even audiophiles often keep recordings on tapes that...