Using the CA3140 integrated circuit, this switch was found in the June 1986 Radio Electronics magazine. Sensitivity adjustment is made at the trimpot in series with the sensor.
Measuring capacitances and resistance this simple instrument was found in Radio Electronics...
The LM143 integrated circuit is a high voltage operational amplifier from National Semiconductor that is...
We found this circuit in the November 1985 issue of Radio Electronics magazine. It uses TTL...