Variable Output Transformers

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46 Products

About AC to AC Voltage Transformers

For single-phase equipment, use this formula to find power output: VA = Volts × Amps

For three-phase equipment, use this formula to find power output: VA = Volts × Amps × 1.73

NEMA 5-15 Plug

NEMA 5-15 Socket

NEMA 5-20 Plug

NEMA 5-20 Socket

NEMA 6-15 Socket

NEMA 6-15 Plug

Mount these portable transformers to any flat surface. Turn the dial to adjust the voltage you need within a given range. Also known as variacs, they are often used in laboratories to vary power, heat, speed, or force.

When wired for constant voltage, transformers filter out voltage spikes and electrical noise.

Voltage
Input	Output	Power Output, VA	Max. Current, A	Input Plug Type (NEMA Style)	Input Cord Lg., ft.	Output Socket Type (NEMA Style)	Ht.	Wd.	Dp.	Features	Specifications Met		Each
Single Phase—Plug Input and Socket Output
Step Up/Step Down/Constant Voltage
120V AC	0V AC-132V AC	330	2.5	Three Prong (5-15)	6	Three Slot (5-15)	5.3"	6.1"	4.1"	Fuse, Power-Indicating Light	CSA Certified	0000000	0000000
120V AC	0V AC-140V AC	700	5	Three Prong (5-15)	6	Three Slot (5-15)	5.3"	6.1"	4.1"	Fuse, Power-Indicating Light	__	0000000	000000
120V AC	0V AC-140V AC	1,400	10	Three Prong (5-15)	6	Three Slot (5-15)	7"	4.6"	5.5"	Fuse, Power-Indicating Light	CSA Certified	0000000	000000
120V AC	0V AC-140V AC	2,100	15	Three Prong (5-15)	6	Three Slot (5-15)	9.4"	6.2"	6"	Fuse, Power-Indicating Light	CSA Certified	0000000	00000000
120V AC	0V AC-140V AC	3,080	22	Three Prong (5-20)	6	Three Slot (5-20)	10.9"	8"	6.3"	Fuse, Power-Indicating Light	__	0000000	00000000
240V AC	0V AC-280V AC	980	3.5	Three Prong (6-15)	6	Three Slot (6-15)	7"	4.6"	5.5"	Fuse, Power-Indicating Light	__	0000000	000000
240V AC	0V AC-280V AC	2,660	9.5	Three Prong (6-15)	6	Three Slot (6-15)	9.4"	6.2"	6"	Fuse, Power-Indicating Light	__	0000000	00000000
Step Down/Constant Voltage
120V AC	0V AC-120V AC	1,440	12	Three Prong (5-15)	6	Three Slot (5-15)	7"	4.6"	5.5"	Fuse, Power-Indicating Light	CSA Certified	0000000	000000
240V AC	0V AC-240V AC	1,200	5	Three Prong (6-15)	6	Three Slot (6-15)	7"	4.6"	5.5"	Fuse, Power-Indicating Light	CSA Certified	0000000	000000

Panel-Mount Variable-Voltage AC to AC Transformers

Permanently install these transformers in panels. Turn the dial to adjust the voltage you need within a given range. Also known as variacs, they are often used in laboratories to vary power, heat, speed, or force. When wired for constant voltage, transformers filter out voltage spikes and electrical noise.

Voltage
Input	Output	Power Output, VA	Max. Current, A	Quick-Disconnect Tab Wd.	Ht.	Wd.	Dp.	Specifications Met		Each
Single Phase—Quick-Disconnect Terminals Input and Output
Step Down/Constant Voltage
120V AC	0V AC-120V AC	210	1.75	0.25"	3.3"	2.9"	1.9"	CSA Certified	0000000	0000000
120V AC	0V AC-120V AC	300	2.5	0.25"	3.3"	2.9"	2.1"	CSA Certified	0000000	000000
120V AC	0V AC-120V AC	360	3	0.25"	3.3"	2.9"	2.4"	CSA Certified	0000000	000000
120V AC	0V AC-120V AC	600	5	0.25"	4.4"	3.8"	3"	CSA Certified	0000000	000000
Single Phase—Screw Terminals Input and Output
Step Down/Constant Voltage
120V AC	0V AC-120V AC	1,200	10	__	5.6"	4.4"	4.2"	CSA Certified	0000000	000000
120V AC	0V AC-120V AC	1,440	12	__	5.6"	4.4"	4.2"	CSA Certified	0000000	000000
120V AC	0V AC-120V AC	1,800	15	__	6.8"	6.1"	4.3"	CSA Certified	0000000	000000
120V AC	0V AC-120V AC	3,000	25	__	8.3"	7.6"	4.4"	CSA Certified	0000000	00000000
240V AC	0V AC-240V AC	1,200	5	__	5.6"	4.4"	4.2"	CSA Certified	0000000	000000
240V AC	0V AC-240V AC	2,280	9.5	__	6.8"	6.1"	4.6"	CSA Certified	0000000	000000
Step Up/Step Down/Constant Voltage
240V AC	0V AC-280V AC	980	3.5	__	5.6"	4.4"	4.2"	CSA Certified	0000000	000000

Ultra-Low Noise Benchtop Power Supplies

Change AC voltage to DC voltage to power extremely sensitive audio, measuring, and testing devices while keeping electronic interference—often called output or ripple noise—from passing on to the device. The lower the output noise value, the less interference the power supplies will create. Although they create less noise than other power supplies, these power supplies are larger, heavier, and give off more heat.

Power supplies with an output voltage selector switch let you toggle between two voltage and current output ranges.

View the output on a digital or analog display. Digital displays are often easier to read than analog displays, so you can quickly see if you need to make adjustments. Analog displays are better than digital displays for monitoring fast output changes, such as dips and spikes.

If you exceed the maximum load or current, all of these power supplies will shut down to protect both the power supply and the connected device. Those with overvoltage or over temperature protection will shut down if you exceed the maximum voltage or temperature.

UL and C-UL listed power supplies meet U.S. and Canadian safety standards.

With One Output Connnection—Digital Display

With Digital Display and One Output Connection

Banana Jack Socket Output
Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Output Connection Location	Output Features	Ht.	Wd.	Dp.	Protections Provided		Each
Single Phase—120V AC, 240V AC Input Voltage
0-18V DC	0-5	0-90	4	Front	Constant Current, Constant Voltage	5.5"	6.5"	10.4"	Overcurrent, Overload, Over Temperature	0000000	0000000
0-30V DC	0-3	0-90	4	Front	Constant Current, Constant Voltage	5.5"	6.5"	10.4"	Overcurrent, Overload, Over Temperature	0000000	000000
0-30V DC	0-6	0-180	5	Front	Constant Current, Constant Voltage	5.5"	6.5"	10.4"	Overcurrent, Overload, Over Temperature	0000000	000000
1-18V DC	0-3	0-54	2	Front	Constant Current, Constant Voltage	4.3"	9.4"	6"	Overcurrent, Overload	0000000	000000
1-30V DC	0-1	0-30	2	Front	Constant Current, Constant Voltage	4.3"	9.4"	6"	Overcurrent, Overload	0000000	000000

With One Output Connnection—Analog Display

With Analog Display and One Output Connection

Banana Jack Socket Output
Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Output Connection Location	Output Features	Ht.	Wd.	Dp.	Protections Provided		Each
Single Phase—120V AC, 240V AC Input Voltage
0-30V DC	0-2	0-60	5	Front	Constant Current, Constant Voltage	4.3"	8"	8.3"	Overcurrent, Overload	0000000	0000000
0-18V DC, 0-36V DC	0-7, 0-3.5	0-126	4	Front	Constant Current, Constant Voltage, Output Voltage Selector Switch	5.5"	12.1"	10.5"	Overcurrent, Overload	0000000	000000

With Two Output Connections—Analog Display

With Analog Display and Two Output Connections

Banana Jack Socket Output
Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Output Connection Location	Output Features	Ht.	Wd.	Dp.	Protections Provided		Each
Single Phase—120V AC, 240V AC Input Voltage
0-30V DC 0-30V DC	0-3 0-3	0-90 0-90	5 5	Front	Constant Current, Constant Voltage	5.5"	12.1"	10.5"	Overcurrent, Overload, Over Temperature	0000000	0000000

With Three Output Connections—Digital Display

With Digital Display and Three Output Connections

Banana Jack Socket Output
Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Output Connection Location	Output Features	Ht.	Wd.	Dp.	Protections Provided	Specifications Met	Includes		Each
Single Phase—120V AC, 240V AC Input Voltage
0-24V DC 0-24V DC 5V DC	0-0.5 0-0.5 4	0-12 0-12 20	6 6 14	Front	Constant Current, Constant Voltage	5.5"	11.8"	11"	Overcurrent, Overload, Overvoltage	__	Three Pairs of Test Leads (Banana Jack to Alligator Clip)	0000000	0000000
0-30V DC 0-30V DC 4-7V DC	0-2 0-2 5	0-60 0-60 20-32.5	3 3 6	Front	Constant Current, Constant Voltage	5.7"	10.5"	15"	Overcurrent, Overload, Overvoltage	UL Listed, C-UL Listed	Two Pairs of Test Leads (Banana Jack to Alligator Clip)	0000000	000000
0-60V DC 0-60V DC 2-7V DC	0-2 0-2 5	0-120 0-120 10-32.5	3 3 6	Front	Constant Current, Constant Voltage	5.7"	10.5"	15"	Overcurrent, Overload, Overvoltage	__	Two Pairs of Test Leads (Banana Jack to Alligator Clip)	0000000	000000

With Four Output Connections—Digital Display

With Digital Display and Four Output Connections

Banana Jack Socket Output
Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Output Connection Location	Output Features	Ht.	Wd.	Dp.	Protections Provided	Includes		Each
Single Phase—120V AC, 240V AC Input Voltage
0-30V DC 0-30V DC 3-7V DC 8-15V DC	0-5 0-5 1 3	0-150 0-150 9-19.5 8-15	3 3 6 6	Front	Constant Current, Constant Voltage	6.3"	10.2"	14.6"	Overcurrent, Overload	Four Pairs of Test Leads (Banana Jack to Alligator Clip)	0000000	0000000

Programmable Benchtop Power Supplies

Use your computer to remotely control these power supplies that convert AC voltage to DC voltage for powering electronics from simple prototypes to advanced testing equipment. All of these power supplies include a USB cable and Windows-compatible software to control, monitor, and record the voltage, current, and power outputs of your device. You can also create programs with up to 20 steps that change voltage and current outputs at set times. A selector switch lets you quickly choose up to three defined settings for voltage and current outputs. The power supplies have an auxiliary output connection, but it will take on the same settings as the primary outputs. View the outputs on their digital display.

These power supplies use switching regulation, which means they produce the stated voltage despite fluctuations in your input power and the power being drawn by your system, and they won’t become too hot. If you exceed the maximum voltage, current, load, or temperature, the power supplies will shut down to protect both the power supply and the connected device.

Power supplies with remote voltage sensing check for any drops in the voltage as they send power to a device. If the voltage dips, they can compensate with extra power, so connected devices always receive the correct voltage.

Maximum output noise is also known as ripple noise. When power supplies convert AC voltage to DC voltage, some noise from the AC voltage will carry into the output. While this noise won't affect most applications, it can interfere with other signals in extremely sensitive audio, measuring, and testing equipment. The lower the output noise, the less interference it creates.

	Banana Jack Socket Output						Front Auxiliary Output
No. of Output Power Connections	Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Output Connection Location	Output Features	Voltage	Current, A	Ht.	Wd.	Dp.		Each
Single Phase—120V AC Input Voltage
1	1-16V DC	0-60	0-960	50	Back	Remote Voltage Sensing, Constant Current, Constant Voltage	1-16V DC	0-5	3.5"	7.9"	10.8"	0000000	0000000
1	1-32V DC	0-30	0-960	50	Back	Constant Current, Constant Voltage	1-32V DC	0-5	3.5"	7.9"	10.8"	0000000	000000
1	1-60V DC	0-15	0-900	100	Back	Constant Current, Constant Voltage	1-60V DC	0-5	3.5"	7.9"	10.8"	0000000	000000
Single Phase—120V AC, 240V AC Input Voltage
1	1-18V DC	0-20	0-360	50	Back	Constant Current, Constant Voltage	1-18V DC	0-5	3.5"	7.9"	8.2"	0000000	000000
1	1-36V DC	0-10	0-360	50	Back	Constant Current, Constant Voltage	1-36V DC	0-5	3.5"	7.9"	8.2"	0000000	000000
1	1-60V DC	0-5	0-300	50	Back	Constant Current, Constant Voltage	1-60V DC	0-5	3.5"	7.9"	8.2"	0000000	000000

Benchtop Power Supplies

Convert AC voltage into the DC voltages needed to test, design, and prototype a wide variety of electrical circuits and equipment. These power supplies let you adjust the output to the exact voltage needed to power your equipment. You can also set limits on the maximum current to protect your equipment from damage. Keep an eye on the voltage and current drawn by your connected components with the digital display.

Since these use switching regulation, they produce the stated voltage despite fluctuations in your input power and the power being drawn by your system, and won’t become too hot.

When these power supplies convert AC voltage to DC voltage, some noise from the AC voltage will carry into the output. While this won't affect most applications, this noise can interfere with other signals in extremely sensitive applications. The lower the output noise, the less interference it creates.

These power supplies are CE Marked, which means they meet European Union safety standards. If your power supply exceeds the maximum current, voltage, or load, they’ll shut down to protect both the power supply and the connected equipment. Some also protect against excessive temperatures.

Power supplies with output voltage selector switch let you choose either an adjustable output, which you control with a dial, or an output fixed at 13.8V DC.

Connect the banana plugs on your equipment to the socket output connections. Power supplies with USB-A output connections can also charge phones and other devices with USB-A ports. You can use more than one output at the same time, but you can’t adjust them independently—all outputs are set to the voltage you select.

With One Output Connection—Banana Jack Socket

With One Output Connection (Banana Jack)

Banana Jack Socket Output						Front Auxiliary Output
Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Output Connection Location	Output Features	Voltage	Current, A	Ht.	Wd.	Dp.	Protections Provided		Each
Single Phase—120V AC Input Voltage
1-30V DC	1-20	1-600	50	Back	Constant Current, Constant Voltage	1-30V DC	1-5	3.5"	7.9"	8.5"	Overcurrent, Overload, Overvoltage, Over Temperature	0000000	0000000
13.8V DC, 3-15V DC	40	552, 120-600	30	Front	Constant Current, Constant Voltage, Output Voltage Selector Switch	__	__	4.4"	11.9"	8.6"	Overcurrent, Overload, Overvoltage, Over Temperature	0000000	000000
Single Phase—120V AC, 240V AC Input Voltage
1-15V DC	60	60-900	40	Back	Remote Signaling, Constant Current, Constant Voltage	1-15V DC	1-3	4.3"	8.7"	14.2"	Overcurrent, Overload, Overvoltage, Over Temperature	0000000	000000
1-30V DC	30	30-900	40	Back	Remote Signaling, Constant Current, Constant Voltage	1-30V DC	1-5	4.3"	8.7"	14.2"	Overcurrent, Overload, Overvoltage, Over Temperature	0000000	000000

With Two Output Connections—Banana Jack Socket and USB-A Socket

With Two Output Connections (Banana Jack and USB-A)

Banana Jack Socket Output				USB-A Socket Output
Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Voltage	Current, A	Power, W	Max. Output Noise, mV DC	Output Connection Location	Output Features	Ht.	Wd.	Dp.	Protections Provided		Each
Single Phase—120V AC Input Voltage
1-36V DC	0-3	0-108	50	5V DC	0.4	2	8	Front	Constant Current, Constant Voltage	6"	2.9"	9.9"	Overcurrent, Overload, Overvoltage, Over Temperature	0000000	0000000

With Three Output Connections—Banana Jack Socket and Lever-Clamp Terminals

With Three Output Connections (One Banana Jack, Two Lever-Clamp Terminals)

Banana Jack Socket Output				Lever-Clamp Terminals Output
Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Voltage	Current, A	Power, W	Max. Output Noise, mVpp	Output Connection Location	Output Features	Ht.	Wd.	Dp.	Protections Provided		Each
Single Phase—120V AC, 240V AC Input Voltage
0-30V DC	0-5	0-150	15	12V DC 5V DC	0.5 0.5	6 2.5	15 15	Front	Constant Current, Constant Voltage	5"	8.5"	11.5"	Overcurrent, Overload, Overvoltage	0000000	0000000

Rack-Mount Power Supplies

With Digital Display

With Analog Display

Mount these power supplies into standard 19”-wide electronics racks, which can hold multiple electronic devices and keep your benchtop clear. These power supplies change AC voltage to DC voltage to power highly sensitive audio, measuring, and testing devices while keeping electronic interference—known as output or ripple noise—from passing on to the device. The lower the output noise value, the less interference the power supplies will create.

Designed with linear voltage regulation, these power supplies produce the same voltage regardless of changes in the input voltage or the amount of current being drawn. They are also known as linear power supplies. As they send power to a device, they use remote voltage sensing to check for any drops in the voltage. If the voltage dips, they can compensate with extra power, so connected devices always receive the correct voltage.

If you exceed the maximum current or load, these power supplies will shut down to protect both the power supply and the connected device.

		Banana Jack Socket Output
Display Type	No. of Output Power Connections	Voltage	Current, A	Power, W	Max. Output Noise Peak-to-Peak, mV DC	Output Connection Location	Output Features	Ht.	Wd.	Dp.	Mounting Fasteners Included	No. of Mounting Holes		Each
Single Phase—120V AC, 240V AC Input Voltage
Digital	1	0-20V DC	0-25	0-500	8	Front	Remote Voltage Sensing, Constant Current, Constant Voltage	5.8"	19"	12.8"	No	4	0000000	0000000
Analog	1	0-30V DC	0-12	0-360	8	Front	Remote Voltage Sensing, Constant Current, Constant Voltage	5.8"	19"	13.5"	No	4	0000000	000000