(DE19705155-A1)      The power supply includes an isolating transformer (Tr1) which has a primary winding (W1), a secondary winding (W2) and a switching transistor (TP21). One end of the secondary winding is connected to a rectifier diode (DS10). A variable zener diode (IS10) is connected downstream of the rectifier diode.    The variable zener diode is used as an error amplifier to regulate the output voltage (UE) of the switched mode power supply or any voltage of another power supply. The anode of the zener diode is connected to earth and the control electrode is connected to the output voltage via a resistor network (RS10-RS13).    USE -   For e.g. electronic entertainment equipment. Also for use in conjunction with car battery.    ADVANTAGE -   Reduces component count and complexity.    (JP10146055-A)      The power supply includes an isolating transformer (Tr1) which has a primary winding (W1), a secondary winding (W2) and a switching transistor (TP21). One end of the secondary winding is connected to a rectifier diode (DS10). A variable zener diode (IS10) is connected downstream of the rectifier diode.    The variable zener diode is used as an error amplifier to regulate the output voltage (UE) of the switched mode power supply or any voltage of another power supply. The anode of the zener diode is connected to earth and the control electrode is connected to the output voltage via a resistor network (RS10-RS13).    USE -   For e.g. electronic entertainment equipment. Also for use in conjunction with car battery.    ADVANTAGE -   Reduces component count and complexity.    (US5973940-A)      The power supply includes an isolating transformer (Tr1) which has a primary winding (W1), a secondary winding (W2) and a switching transistor (TP21). One end of the secondary winding is connected to a rectifier diode (DS10). A variable zener diode (IS10) is connected downstream of the rectifier diode.    The variable zener diode is used as an error amplifier to regulate the output voltage (UE) of the switched mode power supply or any voltage of another power supply. The anode of the zener diode is connected to earth and the control electrode is connected to the output voltage via a resistor network (RS10-RS13).    USE -   For e.g. electronic entertainment equipment. Also for use in conjunction with car battery.    ADVANTAGE -   Reduces component count and complexity.    (US6166923-A)      The power supply includes an isolating transformer (Tr1) which has a primary winding (W1), a secondary winding (W2) and a switching transistor (TP21). One end of the secondary winding is connected to a rectifier diode (DS10). A variable zener diode (IS10) is connected downstream of the rectifier diode.    The variable zener diode is used as an error amplifier to regulate the output voltage (UE) of the switched mode power supply or any voltage of another power supply. The anode of the zener diode is connected to earth and the control electrode is connected to the output voltage via a resistor network (RS10-RS13).    USE -   For e.g. electronic entertainment equipment. Also for use in conjunction with car battery.    ADVANTAGE -   Reduces component count and complexity.