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TREK Model 668B HVPS - High-Voltage Reference Supply

The Trek Model 668B HVPS is a precision, high-voltage, reference power supply with an adjustable output voltage range of 0 to +3 kV DC or 0 to -3 kV DC and an output current capability of up to ±5 mA DC.

The HVPS front panel push-buttons are used to select the desired output voltage with 100 mV resolution. Each decade of the output voltage is independently controlled by its own set of up and down push buttons.

Current control is provided by front panel selection of either supply trip-off or limiting at the preset current value.

Nine programmable memory locations are provided for saving and recalling frequently used output voltage and current settings.

A voltage setting (including polarity) and a current limit or trip value can be stored in each memory location.

The memory locations can be accessed from the front panel or through an optional digital communications interface.

An easy-to-read, sixteen-character LED display indicates the output voltage, the current limit or current value, as well as the memory location currently selected.

The Digital Enable feature provides a connection for a TTL signal or a switching device to turn on and off the high voltage remotely. The optional digital communications interface is well suited for automated test equipment applications.

The 668B HVPS can be operated on a bench top or, with optional hardware, in a 19-inch rack.

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Output Voltage Accuracy
Better than 0.015% of full scale.

Zero Offset Voltage
Less than 50 mV.

Output Noise
Less than 15 mV rms (measured using the true rms feature of the Hewlett Packard Model 34401A digital multimeter).


  • Line
    Better than 0.0025% for a line change from 90 V to 126 V AC or 180 V to 250 V AC.
  • Load
    Better than 0.0025% for a load change from 0 to 5 mA.


  • Drift with Time
    Less than 2 ppm/month, noncumulative.
  • Drift with Temperature
    Less than 25 ppm/°C.


Output Voltage Range
Adjustable from 0 to +3 kV DC or 0 to -3 kV DC.

Output Voltage Resolution
100 mV.

Output Current Range
0 to ±5 mA DC.



Front Panel Display
A sixteen (16) character LED display that indicates the output voltage, the current limit/trip setting, and the memory location.

Front Panel Voltage Control

  • High Voltage On/Off
    Individual push buttons.
  • Voltage Selection
    Up and down push buttons that independently control each of the 5 digits of the displayed voltage.
  • Polarity
    Push-button selectable.
  • Zero
    Push button that commands the output to zero volts.

Current Limit/Trip
Current LIMIT or current TRIP is selected using a single push-button switch. The value is adjustable from 1 mA to 5 mA with push buttons. A LIMIT or TRIP indicator will flash when the instrument is in a current limit or trip condition.

  • Current Limit/Trip Resolution
    1 mA.
  • Current Limit/Trip Accuracy
    Better than 10% of setting.

Digital Enable Feature
An open collector, TTL compatible input to turn on and off the high-voltage output. A TTL high will turn off the high voltage. A TTL low will turn on the high voltage.

Nine (9) programmable memory locations for frequently used output voltage and current settings. A voltage setting (including polarity) and a current value can be stored in each memory location.


Line Supply
90 to 126 V AC or 180 to 250 V AC ±10%, at 50-60 Hz (specify when ordering).

Operating Conditions

  • Temperature
    5 °C to 35 °C.
  • Relative Humidity
    To 75%, noncondensing.

104 mm H x 438 mm W x 394 mm D, (5.09" H x 17.25" W x 15.51" D).

6.9 kg (15.2 lb).

High-Voltage Output Connector
MHV coaxial connector.

Digital Enable Connector
BNC connector.

AC Line Receptacle
Standard three-prong AC line connector with integral fuse holder.



TREK, INC. certifies that each Model 668B is tested and calibrated to specifications using measurement equipment traceable to the National Institute of Standards and Technology or traceable to consensus standards. A Certificate of Calibration accompanies each instrument when it is shipped from the factory.

All specifications are with no load unless otherwise noted and are subject to change.


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