This capacitive sensor that operates with a high frequency oscillator was found in Radio Electronics from the 90's. The circuit operates around 300 kHz.
Found in Popular Electronics from the 90s, this circuit can be used as a warning shield for...
This circuit is from a Popular Electronics from the 90s. The circuit requires extreme care in use, as...
This circuit was found in a 90s Popular Electronics. The frequency is determined by R3 and C1 that...