Capacitance tester for performing capacitance measurements and open and short circuit tests

Claim 1

A CAPACITANCE TESTER FOR DETERMINING THE ELECTRICAL CONDITION OF AN UNKNOWN CAPACITANCE COMPRISING: AN AMPLIFIER MEANS INCLUDING AN INPUT SECTION AND AN OUTPUT SECTION, SAID AMPLIFYING MEANS HAVING A FIRST STATE AND A SECOND STATE, SAID AMPLIFYING MEANS CONDUCTING SUBSTANTIALLY MORE CURRENT IN ONE OF SAID STATES THAN IN THE OTHER OF SAID STATES; A PAIR OF INPUT TERMINALS FOR CONNECTING SAID UNKNOWN CAPACITANCE THEREACROSS; A FIRST CIRCUIT FOR TESTING THE HIGH-FREQUENCY IMPEDANCE OF SAID UNKNOWN CAPACITANCE; A SECOND CIRCUIT FOR DETERMINING THE VALUE OF SAID UNKNOWN CAPACITANCE PROVIDED THE RESISTANCE-CAPACITANCE PRODUCT OF SAID UNKNOWN CAPACITANCE AND THE PARALLEL RESISTANCE ACROSS SAID UNKNOWN CAPACITANCE IS GREATER THAN A PREDETERMINED MINIMUM VALUE; A TEST SWITCH HAVING A FIRST POSITION AND A SECOND POSITION FOR OPERATIVELY ASSOCIATING SAID FIRST AND SECOND CIRCUITS RESPECTIVELY BETWEEN SAID INPUT TERMINALS AND SAID AMPLIFYING MEANS; SAID FIRST CIRCUIT INCLUDING AN OSCILLATOR CIRCUIT COMPRISING A TUNED TANK CIRCUIT CONNECTED TO THE INPUT CIRCUIT OF SAID AMPLIFYING MEANS, SAID TUNED ANK CIRCUIT INCLUDING AN INDUCTIVE MEANS AND A CAPACITANCE MEANS DIMENSIONED TO OSCILLATE AT A PARTICULAR HIGH FREQUENCY, THE OUTPUT VOLTAGE OF SAID TANK CIRCUIT WHEN OSCILLATING PROVIDING A BIASING VOLTAGE TO MAINTAIN SAID AMPLIFYING MEANS IN ON E OF SAID STATES WHEN SAID TEST SWITCH IS IN SAID FIRST POSITION, SAID TANK CIRCUIT WHEN NOT OSCILLATING REMOVING SAID BIASING VOLTAGE TO MAINTAIN SAID AMPLIFYING MEANS IN THE OTHER OF SAID STATES WHEN SAID TEST SWITCH IS IN SAID FIRST POSITION, A CONNECTING CABLE OF SUBSTANTIALLY A QUARTER WAVE LENGTH WITH RESPECT TO SAID OSCILLATING FREQUENCY OF SAID TANK CIRCUIT INCLUDED IN SAID FIRST CIRCUIT AND CONNECTING SAID UNKNOWN CAPACITANCE TO SAID TANK CIRCUIT WHEN SAID TEST SWITCH IS IN SAID FIRST POSITION, SAID CONNECTING CABLE REFLECTING A SUBSTANTIALLY HIGH IMPEDANCE TO SAID TANK CIRCUIT AND HAVING SUBSTANTIALLY NO EFFECT THEREUPON WHEN THE HIGH FREQUENCY IMPEDANCE OF SAID UNKNOWN CAPACITANCE IS BELOW A PREDETERMINED VALUE, SAID CONNECTING CABLE REFLECTING A SUBSTANTIALLY LOW IMPEDANCE TO SAID TANK CIRCUIT TO STOP THE SAME FROM OSCILLATING WHEN THE HIGH FREQUENCY IMPEDANCE OF SAID UNKNOWN CAPACITANCE IS ABOVE SAID PREDETERMINED VALUE TO CAUSE SAID AMLIFYING MEANS TO SWITCH STATES AND THEREBY INDICATE A HIGH IMPEDANCE FOR SAID UNKNOWN CAPACITANCE AT SAID HIGH FREQUENCY; AND