TREK Model 30/20A High-Voltage Amplifier
The Model 30/20A is a DC-stable, high-voltage power amplifier designed to provide precise control of output voltages in the range of 0 to ±30 kV DC or peak AC with an output current range of 0 to ±20 mA DC or peak AC. The amplifier is configured as noninverting with a fixed gain of 3000 V/V. Inverting and differential input options are available. A calibrated potentiometer provides a DC offset over a range of 0 to ±30 kV DC.
Industrial and research applications include dielectric studies, electrostatic deflection, and electrooptic modulation.
The Model 30/20A features an all solid-state design for high slew rate, wide bandwidth, and low-noise operation. The four-quadrant, active output stage sinks or sources current into reactive or resistive loads throughout the output voltage range. This is essential for achieving the accurate output response and high slew rates demanded by reactive loads.
The Model 30/20A is protected against overvoltage and overcurrent conditions that may be generated by active loads or by output short circuits to ground. Precision voltage and current monitors provide low-voltage replicas of the high-voltage output and load current for monitoring purposes or for use as feedback signals in a closed-loop system. The Remote High Voltage Enable feature provides a connection for a remote device to turn on and off the high voltage of the instrument. This makes the 30/20A useful for automated or computer controlled systems.
The Model 30/20A is CE compliant.
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AMPLIFIER INPUT & Output
- Input Voltage Range
0 to ±10 V DC or peak AC.
- Input Impedance
25 kohm, nominal (noninverting).
Inverting and differential option 50 kohm, nominal.
- Output Voltage Range
0 to ±30 kV DC or peak AC.
- Output Current Range
0 to ±20 mA DC or peak AC.
(See Automatic Power Limit feature for limitations.)
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PERFORMANCE
- DC Voltage Gain
3000 V/V.
- DC Voltage Gain Accuracy
Better than 0.1% of full scale.
- Offset Voltage
Less than ±4 V.
- Output Noise
Less than 5 V rms (measured using the true rms feature of the Hewlett Packard Model 34401A digital multimeter).
- Slew Rate (10% to 90%, typical)
Greater than 500 V/µs.
- Large Signal Bandwidth (2% Distortion)
DC to greater than 2.5 kHz.
- Small Signal Bandwidth (-3dB)
DC to greater than 20 kHz.
- Stability
- Drift with Time
Less than 50 ppm/hr, noncumulative.
- Drift with Temperature
Less than 100 ppm/°C.
- Settling Time (to 1%)
Less than 200 µs for a 0 to 30 kV step.
- Automatic Power Limit
Automatically limits the internal power dissipation to protect the Model 30/20A from overheating. The following graph illustrates the Model 30/20A automatic output power limit range (at ±20 mA current limit potentiometer setting).
- Model 30/20A Output Operating Range

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PRODUCT FEATURES
- DC Offset Voltage Adjustment
A calibrated potentiometer adjusts the level of the DC offset voltage from 0 to ±30 kV DC. A three (3) position switch determines positive polarity, negative polarity, or switches the DC offset voltage off.
- High-Voltage Enable
Switch selectable for either local or remote control.
- Local
Individual push-button switches.
- Remote
A TTL compatible input. A TTL high (or open) turns off the high-voltage output. A TTL low turns on the high-voltage output.
- Dynamics Adjust
A graduated one-turn potentiometer is used to optimize the AC response of the Model 30/20A under various load parameters.
- Current Limit/Trip
Switch selectable for either current limit or trip. A graduated one-turn potentiometer is used to adjust the limit/ trip level from 0 to ±20 mA.
- Out Of Regulation Status
An indicator will illuminate and a BNC will provide a TTL low when the Model 30/20A fails to produce the required high-voltage output such as during current limit.
- Limit/Trip Status
An indicator will illuminate and a BNC will provide a TTL low when the high-voltage output is disabled due to the output current exceeding the current trip level, the detection of a high-voltage power supply fault, removal of one of the panels, or if the Model 30/20A is in an out of regulation status for greater than 500 ms.
- Voltage Monitor
A BNC buffered output provides a low-voltage replica of the high voltage output.
- Scale
1/3000th of the high-voltage output signal.
- DC Accuracy
Better than 0.1% of full scale.
- Offset Voltage
Less than ±5 mV.
- Output Noise
Less than 20 mV rms (measured using the true rms feature of the Hewlett Packard Model 34401A digital multimeter).
- Output Impedance
47 ohms.
- Current Monitor
A buffered voltage output provides a representation of the load current.
- Scale
0.5 V/mA.
- DC Accuracy
Better than 2% of full scale.
- Offset Voltage
Less than ±10 mV.
- Output Noise
Less than 30 mV rms (measured using the true rms feature of the Hewlett Packard Model 34401A digital multimeter).
- Bandwidth (-3db)
DC to greater than 5 kHz.
- Output Impedance
47 ohms.
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GENERAL
- Dimensions
91.4 cm H x 43 cm W x 87 cm D
(36" H x 17" W x 34" D).
Depth dimension includes handles and 20 cm (8") of spacing bars to insure proper airflow to the fans on the unit.
- Weight
73 kg (160 lb) approximate.
- High-Voltage Output Connector
Caton high-voltage connector.
- Amplifier Input
BNC connector.
- Voltage Monitor Connector
BNC connector.
- Current Monitor Connector
BNC connector.
- Remote High-Voltage Enable Connector
BNC connector.
- Out of Regulation Status Connector
BNC connector.
- Fault/Trip Status Connector
BNC connector.
- AC Line Receptacle
Standard three-prong AC line connector.
- Power Requirements
- Line Voltage
Factory set for one of two ranges:
104 to 127 V AC or 180 to
250 V AC, at 48 to 63 Hz
(specify when ordering).
- Power Consumption
1800 VA maximum.
- Operating Conditions
- Temperature
0 °C to 40 °C.
- Relative Humidity
To 75%, noncondensing.
- Altitude
To 5000 ft.
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ACCESSORIES SUPPLIED
Operator’s manual, 3 m (10 ft) high-voltage output cable assembly, line cord.
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CERTIFICATION
TREK, INC. certifies that each Model Model 30/20A is tested and calibrated to specifications using measurement equipment traceable to the National Institute of Standards and Technologyor traceable to consensus standards.
All specifications are with no load unless otherwise noted and are subject to change.
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