This circuit for currents from 500 mA to 1.5 A was found on a Ham Radio from the 90s. R4 determines the current in the load under test. Transistors must be equipped with radiators.
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...