Abstract: A power supply arrangement including a transformer and a switching element coupled to a primary winding of the transformer and a power supply. The power supply includes a capacitor having a first terminal coupled to a junction of the primary winding and the switching element and a first diode coupled between the capacitor and an output node. The power supply further includes a discharge element, such as a resistor or a diode, coupled between the junction of the first diode and the capacitor and a power supply common. A voltage regulator, such as a Zener diode, is connected to the output node to produce a regulated voltage powered by the voltage applied to the transformer primary winding, with the regulated voltage being used to power the control circuitry.

Abstract: An epitaxial pinched resistor includes a semiconductor substrate of a first conductivity type having a surface on which an epitaxial layer of a second conductivity type grown. An up isolation region of the first conductivity type is diffused from the surface of the semiconductor substrate up into the epitaxial layer. A first down isolation region of the first conductivity type is diffused down into the epitaxial layer and overlapping with the up isolation region. The first down isolation region and the up isolation region isolate a portion of the epitaxial layer to be used to conduct a current. A second down isolation region of the first conductivity type is diffused down into the epitaxial layer between first and second contact surface areas of the epitaxial layer and into the portion of the epitaxial layer used to conduct the current.

Abstract: An electronic lock is actuatable by an electronic key. The key comprises a plurality of different resistive elements and a signal generator having a plurality of different timing periods. The key further has a signal transmitter. The electronic lock means comprises a lock and a signal receiver. The lock further has a comparator which includes a plurality of different resistive means. The comparator compares each consecutive timing period with the timing period determined by one of the resistive means. The lock further has an activating element for the lock in the event the consecutive timing periods of said signal match the timing periods determined by the plurality of resistive means.