This circuit is from a 1967 documentation. It makes use of varicap and diode tunnel in addition to currently uncommon FET. It serves as a reference.
The presented circuit is suggested by Texas Instruments (www.ti.com) in its Application Report...
This circuit with an industrial standard 4-20 mA interface uses a KPZ20G pressure sensor but can...
This circuit takes advantage of the inductance of the coil of a high-impedance phone to form the...