Abstract: A silicon controlled rectifier device including an SCR portion controlled by an input voltage signal to a voltage comparator and having a latching circuit to permit the SCR portion to remain in the conducting state once switched even in the absence of the input voltage signal. Such a device is especially useful when a narrow input voltage signal is used to switch the SC portion into its conducting state.

Abstract: A load current sharing circuit is disclosed that allows multiple independent power modules, either switching or linear, to be connected in a parallel configuration such that each module delivers only its proportionate share of the load current. Each module measures the common output voltage, compares that voltage to an internal reference voltage signal, and generates an error voltage signal to be used as feedback for regulating its output voltage. The internal reference voltage signal is a function of the extent to which the current within each module differs from the current of the module with the highest current. That module functions as the master, and all the other modules act as slaves. Each slave increases its share of the load current so as to asymptotically approach the load current of the master to within a preset offset voltage, while the load current of the master decreases.

Abstract: A method and device for continuously analyzing, retaining and periodically displaying the concentration of a selected component in an emission gas from a vapor recovery unit. A timing device is provided to periodically display the average concentration of the component in the off gas and the concentration is continuously monitored and supplied to first and second level alarms to be actuated at selected concentrations of the component where when the concentration reaches the first level the concentration is displayed and where if the concentration reaches the second level the vapor recovery unit may be shut down.