Found in a 90’s Popular Electronics, this circuit generates sinusoidal signals with frequency controlled by an input signal. C4, C3 and C1 together with R12 and R3 determine the frequency generated.
This configuration was found in the January 1992 Radio Electronics magazine. The frequency is set...
The microwave sensor of this circuit is a common ceramic capacitor. The circuit is from an 80's...
This sensor circuit for a small robot was found in a Popular Electronics from the 90s. The circuit...