Found in documentation from the 1990s, this circuit supports equivalent transistors. The range is on the order of a few tens of meters.
In fact, the correct name would be a hearing aid amplifier. However, we use the name of the...
With the values of the components indicated, the circuit generates a 1 kHz signal. The power...
This amplifier with old germanium transistors is from a 1957 documentation. The power is a few...