Abstract: An analog memory system is disclosed which uses a temperature sensitive device exhibiting a significant hysteresis centered about a predetermined transition temperature and a significant impedance change about such transition temperature to allow discrimination of a large number of identical temperature impedance levels with conventional electronic circuitry. The memory system comprises means for adjusting the temperature of such temperature sensitive device to write-in an input signal in the form of a predetermined impedance of said temperature sensitive device, means for subsequently adjusting the temperature of said temperature sensitive device at such transition temperature to store the input signal, and a converter for accurately converting the impedance of the temperature sensitive device to an analog of the signal stored in the memory system.

Abstract: A temperature control circuit is disclosed for controlling the firing angle of a thyristor such as a silicon controlled rectifier connected in series with a heater across an alternating power source. The control circuit comprises a field effect transistor having its source and drain electrodes connected for firing of the rectifier when the field effect transistor is rendered conductive, and a bias phase control connected to the gate of the field effect transistor for generating a fixed A.C. voltage component which is phase shifted by about 90.degree. with respect to the voltage of the power source together with a temperature dependent D.C. voltage component to control the firing angle of the silicon controlled rectifier in accordance with the heat generated by the heater, the sum of the A.C. and D.C. voltage components being fed to the gate of the field effect transistor. The temperature dependent D.C.

Abstract: A solid state switching device comprises a temperature sensitive resistive element of V.sub.3 O.sub.5 material which exhibits an abrupt decrease in electrical resistance at about 140.degree.C and electrode lead wires attached to spaced points of such temperature sensitive resistive element for connecting the temperature sensitive resistive element to an electrical circuit.