Abstract: An electrotherapy unit includes a central processor, a digital force modutator connected to and controlled by the central processor, a voltage-increasing transformer, and two conductive pads connected to a secondary coil of the voltage-increasing transformer. The digital force modutator includes two pairs of transistors each having an input side connected to the central processor. The central processor controls conduction/non-conduction of the transistors. A loop for each transistor is connected to the power supply and the primary coil of the voltage-increasing transformer. A diode and a capacitor are connected in parallel between a collector and an emitter of each transistor. The diodes avoid damage to the transistors resulting from an electromotive generated by the primary coil of the voltage-increasing transformer. The capacitors reduce noise signals generated during switching operation of the transistors and the diodes. The capacitors provide bypass for high-frequency noise signals.

Abstract: An electrotherapy unit includes a central processor, a digital force modulator connected to and controlled by the central processor, a voltage-increasing transformer, and two conductive pads connected to a secondary coil of the voltage-increasing transformer. The digital force modulator includes two pairs of transistors each having an input side connected to the central processor. The central processor controls conduction/non-conduction of the transistors. A loop for each transistor is connected to the power supply and the primary coil of the voltage-increasing transformer. A diode and a capacitor are connected in parallel between a collector and an emitter of each transistor. The diodes avoid damage to the transistors resulting from an electromotive generated by the primary coil of the voltage-increasing transformer. The capacitors reduce noise signals generated during switching operation of the transistors and the diodes. The capacitors provide bypass for high-frequency noise signals.

Abstract: A control device for an electric blanket includes a voltage drop rectifier circuit connected to an AC power source, a control gate circuit, a zero-across detecting circuit connected to the AC power source, a central processing circuit connected to the zero-across detecting circuit, an activating circuit, and a button circuit. The control gate circuit includes a triac electrically connected in series to the AC power source. The activating circuit includes an input connected to the central processing unit and an output connected to the gate of the triac of the control gate circuit. The central processing circuit includes a central processor and outputs signals to control the activating circuit, the control gate circuit, and the heating element such that the heating element is activated when the zero-across detecting circuit detects that a voltage of the AC power source approximates zero and thus sends a signal to the central processing circuit.

Abstract: A control device for an electric blanket includes a voltage drop rectifier circuit connected to an AC power source, a control gate circuit, a zero-across detecting circuit connected to the AC power source, a central processing circuit connected to the zero-across detecting circuit, an activating circuit, and a button circuit. The control gate circuit includes a triac electrically connected in series to the AC power source. The activating circuit includes an input connected to the central processing unit and an output connected to the gate of the triac of the control gate circuit. The central processing circuit includes a central processor and outputs signals to control the activating circuit, the control gate circuit, and the heating element such that the heating element is activated when the zero-across detecting circuit detects that a voltage of the AC power source approximates zero and thus sends a signal to the central processing circuit.