We found this circuit in the March 1980 Radio Electronics magazine. The circuit used is the HA2400 released at the time. The power supply must be symmetrical.
This circuit has a voltage gain of 30 times and passband of 14 MHz. The circuit is from the 1974...
In the figure we have an oscillator circuit by Wien Bridge (Wien Bridge Oscillator). The frequency of...
This timer with 1 second accuracy was obtained in a 1973 documentation. The Buzzer is a low-power type...