Electrostatic Voltmeter Instruments

Model 820

Model 820 High Impedance Voltmeter

The Trek Model 820 Contacting Voltmeter represents the next generation of contacting precision surface voltage measuring instruments with features not previously available with any other voltmeter.

Trek developed the Model 820 for voltage measurement applications that demand virtually infinite loading impedance levels which are far beyond the reach of currently available high impedance voltmeter instruments. These applications include accurate reading of electrostatic voltage levels associated with ESD sensitive components, circuits, and surfaces.

Featuring an input capacitance of less than 5 x 10E-13 F and an input resistance of greater than 3 x 10E13 ohms. A guarantee of virtually no modification of the charge (voltage) of the measured object is obtained. This allows the Model 820 to indicate, with high precision, the voltage level of both conductive and insulative objects and surfaces.

A rear panel USB Connector allows data transfer to a computer with a sampling rate of either 1 ms or 10 us between data points (stream data or block data transfer protocols). PC software records and graphs the unit's output.

With virtually zero charge exchange upon probe contact, no ESD events, which would normally cause object damage, can occur. These near infinite impedance features allows direct measurement of such devices as semiconductor components and chips, insulative surfaces, MR head sensors, hand tools, etc.

PERFORMANCE

Measurement Range
0 to ±2 kV DC or peak AC.

Accuracy a t the Voltage Monitor Output
Better than ±0.1% of full scale.
Accuracy a t the Voltage Display
Better than ±0.1% of reading ±1 digit (referred to measured input).

Large Signal Bandwidth (-3 dB)
DC to greater than 200 Hz.

Small Signal Bandwidth (-3 dB)
DC to greater than 5 kHz.

Input Characteristics
Resistance greater than 3 x 10E13 ohms .
Capacitance less than 5 x 10E-13 F.

Stability
Drift with Time (at 22 °C)
Less than 6 V/minute, accumulative [referred to input].

PRODUCT FEATURES

• Digital Enable
  An open collector, TTL compatible input to enable or
  disable the unit's high-voltage measurement. A TTL high
  will disable while a TTL low will enable the measurement.

  Voltage Display
  3½ digit LED display.
  Range
  0 to ±1999 V.
  Resolution
  1 V.
  Zero Offset
  Less than or equal to ±1 count.

  Voltage Monitor Output
  A BNC provides a buffered low-voltage replica of the measured voltage.
  Scale Factor
  1 V/200 V (standard).
  Output Current
  ±5 mA (minimum).
  Output Noise
  Less than 10 mV rms.
  Output Impedance
  Less than 0.1 ohms.

• USB Connector
  Allows data transfer to a computer with a sampling rate of 1 ms or 10 us between data points (stream data or block data transfer protocols). PC software records and graphs the unit's output.

  Reset Button/Connector
  A momentary front panel push-button switch or rear panel external TTL input signal initiates a reset function. A momentary TTL low signal will initiate the reset function. A TTL high (or open) allows normal operation.

PROBE

Model 820 Probe
Probe connects to the front panel and may either be hand-held or mounted to a clamping device.

Sensor
0.8 mm conducting ceramic electrode (sensors may be easily replaced
dependent on the measurement requirements).

Orientation
Pencil probe structure with end contact sensor.

Probe Dimensions
152 mm L x 20 mm Diameter
(6" L x 0.75" Diameter)

Probe Cable Length
1.5 m ±76 mm (5.3 ft. ±3 in.).

ACCESSORIES

• Model 820P probe, operator's manual, PC software, AC/DC Universal Power Cube, and ground cord.

GENERAL

• Power Requirements
  Available for all nominal line voltages, the Universal wall cube provides the following input power to the ESVM:
  Voltage
  24 V DC, ±5% @ 1 Amp.
  Input Connector
  2.1 mm DC power plug.

  Dimensions
  62.5 mm H x 228 mm W x 257 mm D
  (2.5" H x 9" W x 10" D).

  Weight
  1 kg (2.2 lb).

  Voltage Monitor Connector
  BNC connector.

  Digital Enable Connector
  BNC connector.

  Reset Connector
  BNC connector.

  USB Port
  Type B port.

• Ground Receptacle
  Threaded ground stud.

• Operating Conditions
  Temperature
  10 °C to 35 °C.
  Relative Humidity
  To 75%, noncondensing.

  Power ON/OFF
  A momentary push-button.

  Probe Connector Location
  Front panel