The LPF (23) extracts low-frequency components from the input signal and supplies them to a voltage-controlled oscillator (24).

A first switching transistor, responsive to the control node voltage, controls conduction of a second switching transistor connected between the d-c voltage source and a voltage regulated driver circuit.

The A/D converter has a voltage controlled current source (16), a capacitor (18), a Schmidt trigger (22), a counter (6), and a transistor switch (20).

The reference signal synchronizing unit (550) comprises a count circuit (551), a comparator (553), a low-pass control filter (554), a D/A converter (555) and a voltage controlled oscillator (556).

Each generator is regulated via its associated voltage regulator at a common regulation voltage.

The phase displacement is regulated by a control voltage (Vc) as a function of the variations in the output voltage (Vs) of the converter.

The voltage-controlled delay is controlled by the control voltage developed by the phase-locked loop amplifier and filter (410).

Current between the source and the drain is controlled by applying a voltage to the gate electrode.

Current through the smaller transistor is controlled by the voltage control loop such that the voltage on the output terminal is regulated to a predetermined voltage .

A variable resistor (28) is used to set the regulated level of the voltage output.

The fifth resistor has a value chosen to drop a voltage equal to the target voltage to be regulated when the voltage regulator output is equal to that target voltage.

The rate of metal ion elution is regulated by varying the voltage applied between two types of metal bodies.

Certain embodiments include a bidirectional buck converter (26, 28, 30, 32, 34) that converts an unregulated DC flow to a regulated DC flow through an inductor.

The intensity is changed by modifying a voltage bias (VG1) in a current mirror regulated current driver.

A current-regulating circuit controls the supply current of a magnetic coil in function of a pulsed voltage which is modulated by a modulator in function of a reference voltage and an actual voltage.