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Array 3721A 400 Watt Programmable DC Electronic Load 0-80V, 0-40A

Item no. CSI3721A
Save $100.00 Free shipping

Array 3721A 400 Watt Programmable DC Electronic Load 0-80V, 0-40A

Item no. CSI3721A
$595.00 $695.00
7 In stock

400 Watt, 0-80 Volt and 0-40 Amp Programmable DC Electronic Load

Like many Circuit Specialists products, the Array 3721A is shipped and supported from the USA.

The Array 3721A Programmable DC electronic load provides excellent all around performance with sophisticated features found on much more expensive units. This 400 watt, 40 Amp, 0-80 volt programmable load can be used to test all manner of DC power sources including batteries and power supplies and is especially useful in the battery manufacturing process. This DC load features constant voltage, constant resistance, constant current and constant power settings, for uniform, repeatable results. Users can easily design programs that precisely control all of the load values and time durations for each step of a test sequence. Up to nine separate ten step programs can be internally stored in the Array.


The Array 3721A DC Programmable Electronic Load is the ideal DC Load for all of your power source testing needs. This electronic load is easily controlled from the front panel keypad or rotary control knob, or with software through the serial port or USB port from a personal computer. You can control and acquire data from the electronic load via USB port with the addition of an RS-232 to USB null modem adapter. Designed to be easy to use, offer maximum flexibility and still highly reliable; the 3721A programmable DC load is an excellent choice for all of your power source testing needs. This unit operates on standard 115VAC input or can be switched to take a 220VAC input via rear panel selector switch.

The Array 3721A programmable load has four basic functions for test programs: constant current, up to 40 amps; constant voltage, up to 80 volts, constant resistance and constant power, up to 400 watts. The constant resistance mode utilizes improved circuitry to enhance the dynamic response which widens the application scope. The constant power mode allows testing of voltage sources, current sources, and effectively can prevent a short-circuit if insufficient test power is used. These four functions allow eight basic test modes: constant current, low; constant current, high; constant resistance, low, medium and high range; constant power, voltage source mode and current source mode. Beyond these standard tests, there are a few auxilliary functions that allow more specific testing: high speed sequencing, high speed transient, short circuit, and battery discharge.

Due to the power levels involved, the 3721A is packed with protection circuitry including a high-speed, power limiting circuit to limit input power. It also goes into protection mode during over current, over voltage, over temprature and reverse polarity conditions. Also, like most Array products, the 3721A comes with a 1 year limited warranty.

Array 3721A Specifications

  • Inputs: 1
  • Input Voltage: 0~80V
  • Input Current: 0~40A
  • Input Power: 0~400W
  • Ripple: 5 mVrms
  • Voltage Accuracy: 0-80V: ±0.1%+10mV
  • Current Accuracy:
    • 0-4A: ±0.1%+5mA
    • 0-40A: ±0.1%+10mA
  • Maximum Resolution:
    • Voltage: 1 mV
    • Current: 0.1mA
    • Included 24 bit analog to digital and 17 bit digital to analog converters at 100kHz
  • Minimum Conductive Resistance: < 0.02 ohm
  • Protection: Over voltage/Over current/Over power/Over temperature/Reverse Polarity
  • Interface: RS232& USB (GPIB Interface is optionally available)
  • AC Input: 110V/220V AC +/-15%, 48~63Hz (switchable)
  • Operating environment: 0~50deg C, 85% RH
  • Dimensions: 414mm Wide x 110mm High x 226mm Deep
  • Standard Accessories: Power cord, users manual, USB adapter cable
Remember, for use on a computer with only a USB port, we recommend the ICUSB232FTN USB to RS-232 Null Modem Adapter.

For more information, refer to the Array 3721A's Owners Manual.

For assistance getting started, refer to the Array 372X Series SCPI programming guide.

Helpful Links

Here you can download the LabView source code V1.0.

You can update the Array 3721A's firmware, here.

For more information on the many uses of an electronic load check out this link to the CS blog.


1-year limited warranty

30 day satisfaction guarantee
Satisfaction Guarantee
Your satisfaction is important to us. If you're not satisfied, return the product within 30 days of purchase for a refund or credit.

Return policy
One year warranty
Limited Warranty
Circuit Specialists wants you to be happy with your purchase. This product comes with a one-year limited warranty.

Warranty policy
Free tech support
Free Tech Support
Circuit Specialists offers free technical support for the life of your product. Please call our technical team with any questions.

1-800-528-1417 ext. 3
Mon - Fri: 8:00 AM - 5 :00 PM (MST)

Expected delivery within 3-7 business days after shipping. Free shipping offer applies only to orders that weigh under 150 lbs. Offer limited to the contiguous U.S. Certain exclusions and limitations may apply. Circuit Specialists reserves the right to modify or discontinue any offer at any time.

Some products must be specially ordered, usually resulting in a 1–2 business day delay. Please contact us for an estimated delivery date.