DIAC

Abstract: Switch devices, such as Silicon Controlled Rectifier (SCR), DIAC, or TRIAC, on a semiconductor body are disclosed. P/N junctions can be built on a semiconductor body, such as polysilicon or active region body on an insulated substrate, with a first implant in one end and a second implant in the other end. The first and second implant regions are separated with a space. A silicide block layer can cover the space and overlap into both implant regions to construct P/N junctions in the interface.

Abstract: A test circuit (1) for arc fault detectors (19) of the type which respond to step changes in ac current over time generated each time an ac is struck includes a low frequency relaxation oscillator (43) which generates a repetitive signal with step changes like those produced by an arc fault. The relaxation oscillator (43) includes a capacitor (47) charged through a resistor (49) and shunted by a voltage breakdown device (51), preferably a diac. The capacitor (47) is rapidly discharged when its voltage reaches the breakdown voltage of the voltage breakdown device (51) to generate the step change which is input to the arc fault detector (19). With a repetition rate of the relaxation oscillator not greater than about 15 repetitions per second (rps), and preferably about 5 rps, a user can annually determine the time to trip to verify arc fault detector operation. With the oscillator operating at such a low frequency, a signaling device (67) such as a light emitting diode (LED) placed in series with the voltage breakdown device (51), permits the user to manually count the number of step changes required to produce a trip thereby providing further verification of detector operability.

Abstract: An inverter is adapted to be powered from full-wave-rectified unfiltered 60 Hz power line voltage and to provide an amplitude-modulated output of relatively high-frequency voltage. The inverter has to be triggered into oscillation. However, once triggered, it will continue to oscillate--but only for as long as its DC supply voltage is present. Since the DC supply voltage falls to zero magnitude once for each half-cycle of the 60 Hz power line voltage, the inverter stops oscillating after each such half-cycle; and therefore, for as long as output voltage is desired, the inverter has to be re-triggered after each half-cycle. Triggering is accomplished by a Diac in combination with an RC integrating circuit; which means that the inverter is triggered into oscillation some time period after the onset of each half-cycle. The length of this time period is determined by the nature of the RC integrating circuit, in the same way as phase-control is accomplished in an ordinary Triac-type incandescent lamp dimmer. By varying the time-constant of the RC integrating circuit, the inverter can be triggered into oscillation with varying amounts of delay; which means that the net effective RMS magnitude of the output voltage can be adjusted by adjusting the time-constant of the RC integrating circuit.

Abstract: An electric series circuit with plural loads such as light bulbs connected in series and plural solid state switching devices, with each switching device connected in parallel with one of the loads. Each switching device conducts current when the load that it is connected in parallel with does not conduct current because the load is burned out. The solid state switching means may be any device. with a breakthrough voltage which is high enough that it does not conduct when all of the loads conduct current normally. When one of the loads is burned out, that load does not conduct current and the entire line voltage appears across the switching means in parallel with the burned out load. The switching means breaks down. Accordingly, the switching means conducts current and current flows to the remaining loads. Accordingly, the remaining light bulbs in a string of light bulbs continue to light. The burned out load may be immediately detected and replaced. The switching means may be a sidac. Alternatively, a combination of an SCR and a zener diode controlling the gate of the SCR are also disclosed as the switching means. A diac may replace the zener diode.