We found this circuit in an English publication from the 1980s. The circuit uses current components and can be tuned for frequencies between 300 and 1500 Hz.
This fixed regulator for currents up to 2 A uses a 741 operational amplifier. The transistor must...
Using a zener diode it is possible to change the linearity of the scale of an analog instrument by...
This high sensitivity circuit was found in the July 1992 Radio Electronics magazine. The circuit...