This circuit consists of an inverter powered by only 4.5 V. The circuit is from a 1967 Mullard documentation. No information was provided on the transformer winding. Capacitors can be 1.5 nF x 3 kV.
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...