This circuit was found in a Popular Electronics of the 90's. The circuit makes use of common components today and several sensors can series connected.
This basic 100 kHz oscillator is suitable for use in calibration. We found it in documentation from the...
Found in a 1968 EEE, this circuit accepts frequencies from 1 to 1000 Hz and control voltages from 0.1 to...
National Semiconductor suggests the circuit shown in the figure for amplifying signals from two...