With this circuit it is possible to modulate pulses from a pulsating input signal. The PNP transistor can be the BC558 and the power must be supplied with 5 V.
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...