Abstract: A pair of a first and a second R-C integrating circuits connected in series. A first switch S.sub.1 supplies a first combined voltage E.sub.1 +E.sub.3 of a first positive threshold voltage E.sub.1 and a positive initial set up voltage E.sub.3 to a first capacitor in the first R-C circuit, and a second switch S.sub.2 supplies a second capacitor with a second combined voltage of a second positive threshold voltage E.sub.2 with a negative initial set up voltage -E.sub.4. The switches S.sub.1 and S.sub.2 are closed before the input of the signal to be measured. The switches are opened after the input of the signal. A first comparator compares a first discharged voltage output from the first capacitor and the first threshold voltage E.sub.1, and a second comparator compares a second discharged voltage output from the second capacitor and the second threshold voltage E.sub.2.

Abstract: A plug board for testing integrated circuits includes a plurality of sockets for receiving the terminals of an integrated circuit to be tested, a plurality of contacting terminals arranged in an annular layout and electrically connected to the sockets, an annular grounding belt electrically connected to the contacting terminals and adapted to be grounded, and a drive system adapted to rotate the plug board about the center of the contacting terminals.

Abstract: An apparatus for testing plug-in type integrated circuits by applying a potential across their input and output terminals, utilizing a socket board with a plurality of sockets bored therein to receive respective input and output terminals of an integrated circuit. A pair of first and second groups of fixed contacts are located in the socket board, arranged in two concentric circles enclosing the sockets. Each fixed contact in each group is individually connected to one of the sockets through a conductor. A pair of coaxial first and second moving contact pins is rotatably disposed below the socket board. The first contact pin rotates to follow the first circle while sequentially contacting the contacts of the first group. The second contact pin follows the second circle, making sequential contact with the fixed contacts of the second group.

Abstract: A power controlling circuit for automatic temperature regulator or the like using a zero voltage switching control. Clocks are dispersed and selected, in accordance with control factor, from among the clocks synchronized with the load power supply when zero voltage is detected from the load side to perform the zero cross control of the energization to the load through the detection of the zero voltage from the load side thereby to drive the zero cross control by the selection clock. The current limit close to the phase control can be achieved without any production of the noises. Also, the power control can be achieved without any production of the noises and does not damage the resolution and response property.