• DJOP series
  • DJOP series

DJOP series

Compact High Speed
Bipolar Power supply

  • Output Voltage: ±10V to ±60V
  • Max output power:
    50W, 60W
  • Frequency bandwidth:
    DC to 30kHz
  • Wide lineup

Four-quadrant fast response bipolar power supply

DJOP series are four-quadrant bipolar power supplies which source and sink electric power. They can be used in 2-mode of a CV (constant voltage) or a CC (constant current). Thanks to the original design, phenomenal light weight and compact size power supply, which is 140 mm width, and weigh 3 kg has been achieved. They are ultra compact and high speed, driving output propor-tional to the input waveform such as a sine wave, triangular wave, saw wave, and square wave. All the models are completely solid-state with output voltage between ±10 V to ±60 V. DJOP series is most appropriate for evaluation test such as solar panels, the instruments driven by battery and the IC which control battery.

Even faster model, DOS series, amplifier with function generator, DOPF series, or more high power model, DOP series, are available. Contact to local sales office for details.

Notice of POWER switch changes

We inform you of the power switch changes on the front panel as in the diagram below for shipment from June, 2020.

Before After
Push button switch
DJOP's Push button switch
Rocker switch
DJOP's Rocker switch

For further information, please contact our sales representatives.


Response speed
Newly developed DJOP Series is the most appropriate for transient response test with such high power and broad bandwidth.
Compact & light weight
For maximum compactness and light weight, DJOP Series has been improved for small footprint and easy carry.
Four-quadrant action
DJOP Series can be used both as a high speed response DC power supply and as an electronic load.
CV (constant voltage)/CC (constant current)
A single switch selects between CV and CC modes.
DC bias
10-turn potentiometer to be used for the output setting volume when used as the DC power supply and for the bias setting when used as AC power suppluy is equipped.
Wide lineup
Select a model fitting for your applications from the lineup of various output voltage and current.
DC output meter
3-digit digital meter displays the DC value of the output voltage and current. (The option of rms indication is available.)
Complete protective function
Protective function against over voltage/current and protective measures against output short-circuit are completely provided.


  • Suitable to evaluate battery driven equipment to use as a simulated battery
  • Inductive load such as coil and transformer
  • Capacitive load like capacitor
  • Various motor tests
  • voltage regulation tests for in-vehicle electrical component
  • Evaluation test for solar panel related devices
  • For surface treatment

This product is not designed for charge and discharge of battery. Please contact nearby sales if unit is used for charge and discharge application.


Model Maximum output Frequency bandwidth [kHz (-3 dB)]
Voltage [V] Current [A] Power [W]
DJOP10-5 ±10 ±5 50 DC to 30
DJOP20-3 ±20 ±3 60
DJOP30-2 ±30 ±2 60
DJOP60-1 ±60 ±1 60



OVP (Over voltage protection)

DJOP series is equipped with over voltage protection, which protects load by limiting voltage up to approx. 110% of the rated output voltage even at abnormal conditions.

OCP (Over current protection)

DJOP series is also equipped with over current protection, which protects power supplies and load by limiting current up to approx. 110% of the rated output current.

High speed over current protection

DJOP series is provided with 2 types of over current protections, high speed over current protection to limit the pulse current, and standard over current protection to limit the static current. The standard over current protection limits the static current, responding at around 1 ms. Additional high speed over current protection can limit pulse current of square waveforms or from capacitor at approx. 2 times more current of rating.

High speed over current protection

Output range

DJOP series is a bipolar power supply which can perform four-quadrant operation. They can supply (source) and absorb (sink) current in the field of the drawing on the right.

  • Vo max: rated output voltage
  • Io max: rated output current
Output range

CV/CC setting selection

Inputting voltage via Vcon-in enables the control of output voltage V when CV control is selected and output current A when CC control is selected.

in CV mode in CC mode
Vcon Output voltage Output current
-10 V -Rating -Rating
0 V 0 V 0 A
+10 V +Rating +Rating

Use of BIAS

When the "BIAS ON/OFF switch" is flipped to ON, bias can be changed with the "BIAS setting dial." Bias of the voltage can be set when CV control is selected, and that of the current can be when CC control is selected.

in CV mode in CC mode
Scale Output voltage Output current
000 (ccw) -Rating -Rating
500 0 V 0 A
1000 (cw) +Rating +Rating



inch (mm)






  1. POWER ON/OFF switch
  2. OUTPUT ON/OFF switch
  3. Output Voltage meter
  4. Output current meter
  5. CV/CC select switch
  6. Vcon-in terminal
  7. Bias ON/OFF switch
  8. Bias setting dial
  9. Control connector
  10. Output terminal
  11. AC input terminal


For details, download the datasheet below.


-LN: No protection against blackout

How to Order

To order, please add the above option codes to the model number.


For details, download the datasheet below.


AC input cable


125 V/10 A (Standard)


250 V/10 A (Sold separately)


250 V/10 A (Sold separately)


Tech Notes

Rise time

(Stepping time): The response time is sometimes described by the rise time (as shown in the drawing on the right). The rise time of an amplifier at a response speed of (= frequency bandwidth) Fc (Hz) is generally acquired by "tr ≒ 0.35/fc." Fall time tf is the same as tr. Frequency bandwidth
: at 30kHz or lower, tr = tf = around 12 μs

Rise time

Response speed

When accurate output waveforms are required, select a amplifier with a frequency bandwidth higher enough than the operating frequency. In case of using sine waves, 3 times to 5 times more frequency bandwidth is required, and around 10times more in case of square waves in general. Inadequate bandwidth causes not only decrease in the output amplitude but much difference between the input and output phases. Therefore operating the product while monitoring the actual output waveforms is recommended.

Response speed

Inductive load

Some inductance of inductive load may cause resonance in CC mode.
In such cases, connect a C-R series circuit between output terminals to prevent resonance.

Capacitive Load

When a capacitive load is more than 100 pF (including a stray capacitance of output wire), the resonance in the output may occur. In that case, install 100-ohm (@0.1 μF) to 1000-ohm (@1000 pF) of high voltage resistance in the output in series. Please note that the frequency band will be limited as the formula written in the right figure when an amplifier is used with a capacitive load.
In addition, when an amplifier is used for the use such as a corona discharge, the current which is higher than rating will flow and it will affect the amplifier badly. In this case, as well as the time to use an amplifier with a capacitive load, please install the output resistance and limit the current.

* Please avoid continuous inputting of high frequency signal which reduces output frequency of an amplifier. An amplifier will be broken because of increase of internal loss.

This image explains frequency band when a capacitive load is connected.

Read more


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Bipolar power supplies/High voltage Amplifiers