This circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit is based on a 741 that activates a buzzer with oscillator. R5 adjusts the sensitivity.
An integrator of exceptional qualities is obtained around an LM108, as shown in the figure. The...
The integrated circuit used in this regulator is quite old. Its 1970s casing is still made of...
This unijunction relaxation oscillator can be used as a very useful signal injector. The circuit is...