Electronic Test Equipment-Namely, Capacitance Measurement Apparatus, Logic Probes, Electrical Potential Detection Apparatuses, Capacitance Limits Comparator Apparatus, Micro-Processor Based Electronic Test Instruments for Measurement of Capacitance, Inductance, Resistance, Voltage, Current Conductance and Frequency, and Various Computer Interface Instruments for Connection and Control of General Input and Output Devices to Standard Micro-Computers