Electrometer Keithley 610C - Voltage measurement Normal Voltage Measurement The Keithley 610C Electrometer can be used as Voltmeter with input resistance greater than 1014 Ω and voltage ranges from 1mV full scale to 100 Volts. Set the controls as follows: ZERO CHECK switch LOCK RANGE switch VOLTS Multiplier switch 100 FEEDBACK switch NORMAL METER switch CENTER ZERO Connect the input source to the UHF input connector. Unlock the ZERO SWITCH to make a reading. Increase the meter sensitivity using the Multiplier switch to obtain a usable on-scale reading. The METER switch should be set to either + or - to obtain the rated voltage accuracy. Guarded Voltage Measurement This method is usable with a triaxial cable. The inner shield (guard) of triaxial cable must be connected to the X1 OUTPUT on the rear panel of the instrument. The outer shield of the triaxial cable (ground) is connected to the outer of UHF connector and input high of the triaxial cable is connected to input (inner plug) of the UHF connector. Set the controls as follows: ZERO CHECK switch LOCK RANGE switch VOLTS Multiplier switch 100 FEEDBACK switch NORMAL METER switch CENTER ZERO High Voltage Measurement Measurements can be made up to 30 kV using a Voltage Divider Probes. The full scale voltage range is determined by multiplying the divider ration times the Multiplier setting.

Electrometer Keithley 610C - Resistance measurement Normal Resistance Measurement When the FEEDBACK switch is set to NORMAL, the resistance is determined by measuring the voltage drop across the unknown resistance shunting the input. The Keithley 610C injects a constant current a the input terminals. The voltage drop is therefore proportional to the resistance. Ohms Guard Resistance Measurement This method is recommended for measurements from 100 GΩ to 100 TΩ. The unknown resistor is connected between INPUT high and GUARD on the rear panel of the instrument. Voltag-Ampere Resistance Measurement This method is useful when the voltage drop across the unknown resistance must be accuratelly controlled. The instrument is used in the NORMAL mode with RANGE switch to AMPERES. One lead of the unknown resitor is connected to input (inner plug) of the UHF connector.The second lead is connected to a switch. The switch connect the resistor either to Ground of the UHF connector or to known voltage. To determine the resistance the MULTIPLIER setting should be substracted from the voltage source setting. The resistance is therefore the ratio of the next voltage divided by the current measured by the instrument.