This circuit was found in an old Poptronics. Operational amplifiers can be replaced with equivalents. The power supply must be symmetrical.
This receiver is from a 1967 Japanese publication. The transistors are germanium and the output...
The basis of this project is a three-position lever switch or similar. When the switch is in the...
The astable multivibrator shown by the figure can produce signals in the 10 to 10 000 Hz band...