This proximity sensor was found in a 90s Popular Electronics. The base is a PLL567 that operates at around 100 kHz. The circuit operates by capacitance sensing.
We present a comparator with signal resolution in the submicrovolt range. The matched pair of...
We found this circuit in an Argentine publication from the 1970s. The circuit can be used to...
Found in a 1968 Motorola manual, this DC circuit uses components from the era. The circuit fires in...