We found this tube receiver in a 1950s Japanese publication. The circuit uses 5 tubes and has an RF amplifier stage for greater sensitivity. The power supply is not shown on the circuit.
We can implement this filter with more modern equivalent operational amplifiers, since the LM110 is...
This stethoscope or amplifier for hearing aid using a crystal headset and microphone was found in a...
The normal use of a 4520 as a divide-by-16 counter is shown in Figure bellow. In the normal...