This is the 1968 MR480 commercial cassette recorder circuit. The circuit was fully transistorized and powered by 4 large batteries. We found the diagram in a Japanese documentation of the time.
With this circuit it is possible to divide the frequency of a rectangular signal by values between 2...
This circuit, which we find in a documentation from the 70s, filters out the Ru [occurring in...
This circuit simulates the call tone of a telephone. The transducer is a high impedance capsule, and...