free shipping at parts express

Manuals & Resources

Parts Express 3A Variac Variable AC Power Transformer 0-130 VAC

Brand:|Model: SC-3M|Part # 120-840
An essential component of any test bench, a variac autotransformer allows the user to adjust incoming 110/120 VAC to 0~130 VAC via a dial.
In Stock
Your Price
Buy 4+$58.18
Part # 120-840
  • Easy operation by the knob on top of the unit
  • Meter makes it easy to see output voltage
  • Tabletop unit has 3A current capacity

Product Details

Parts Express 3A Variac Variable AC Power Transformer 0-130 VAC

A variac is an extremely handy device that allows the user to dial 110/120 VAC wall voltage up or down from 0~130 VAC, measured by a meter on the front of the unit.

Most often, variacs are used on test benches, either to troubleshoot problems, test experimental circuits, or slowly power up vintage electronics to evaluate and perhaps recondition aging internal components.

They're also used in performing arts and cinematography to control lighting. In areas where line voltage runs higher than standard, use of a variac can improve the function and longevity of electronics.

Current capacity: 3A.

Parts Express 3A Variac Variable AC Power Transformer 0-130 VAC
  • BrandParts Express
  • ModelSC-3M
  • Part Number120-840
  • UPC848864002750
  • Product CategoryVariac Variable Transformers
  • Unit of MeasureEA
  • Product Rating
    (2 Reviews)
  • Weight6.5 lbs.
  • California Prop 65

    Warning: California residents only. Please note per Proposition 65 that this product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

View similar products to the Parts Express 3A Variac Variable AC Power Transformer 0-130 VAC
in the Variac Variable Transformers product category.


Parts Express 3A Variac Variable AC Power Transformer 0-130 VAC
Parts Express 3A Variac Variable AC Power Transformer 0-130 VAC is rated 5.0 out of 5 by 2.
Rated 5 out of 5 by from 3A Variac AC Power SupplyThis item is better than I expected. Arrived quickly, packaged securley and works like a charm. The meter is very accurate and the variac does not hum. Just what I needed at the best price around. Thank you Parts Express.
Date published: 2014-09-14
Rated 5 out of 5 by from Optimum unit for hot wire cutting EPS foam.I have used this item on virtually all of the stylus pattern EPS foam cutters, of which I am the original designer, and have sold for more than 20 years. It is absolutely the smartest way to power a foam cutter. The voltage adjustment is infinite from 0 to 130 volts. You typically need only about half the output to power a 60-inch, .014: inconel .wire, which is the ONLY wire to use when cutting EPS foam. It is the strongest, quickest to heat up, and with the least amount of stretch.This power supply comes ready to use. Simply alter a two-wire extension cord (eliminate the green ground if using 3-wire type) and attach the black and white wires to each end of the cutting wire. First make sure the unit is turned to zero. Plug the variable transformer into any 120-volt AC outlet and then plug the altered extension cord into the outlet on the front of the unit. Place a piece of EPS foam on top of the cutting wire which must be elevated so the foam piece will drop down when you turn up the voltage. I have found that the optimum heat is obtained when smoke rises from the cutting wire almost immediately after it has passed through the foam. This is the styrene residue burning off the wire. By keeping the wire elevated, and slowly increasing the voltage, you then pass a test piece of scrap EPS foam across the inconel wire allowing you to obtain the optimum heat. Good luck.
Date published: 2014-08-08
  • 2016-02-13T07:06CST
  • bvseo_cps, prod_bvrr, vn_cps_3.1.6
  • cp_1, bvpage1
  • co_hasreviews, tv_0, tr_2
  • loc_en_US, sid_120-840, PRD, sort_mostRecent
  • clientName_PartsExpressInternational

Product Q&A

Get your questions answered from other customers
who own this product or have experience with it.
If your question requires design or troubleshooting information,
please email  for a prompt reply.
Parts Express 3A Variac Variable AC Power Transformer 0-130 VAC

I am looking for something to take the 117v that comes from my wall plug (I tested it and it is 117) and turn that into 120 v to run a coffee roaster. I don't what the amp load aspect is? The roaster apparently draws between 15 and 20 amps.

Asked by: freakydrew
If the unit you have absolutely needs 120 VAC to work properly, you will need to use a power conditioner that regulates output power. I highly doubt this is required, most standard wall powered items work with voltages from 110-120. I would recommend contacting the manufacturer to verify this.
Answered by: MattP
Date published: 2014-11-28

can this be used with a heating mantle rated at 350 Watts, 110 volts. I'd be using the variac mainly to decrease the volts and the heat generated.

Asked by: cocoleka
Well, at 3amp--110volts, you are right at the line. I suggest a higher amp unit for safety. I'm not saying that this won't work, but experience tells me that anything to do with 110/120 volts,[or higher] a safety margin of 10 to 20% insures not just safety, but long useful life of the unit. See suggestions below.
Answered by: Joe from San Francisco
Date published: 2013-10-22
  • 2016-02-13T07:55CST
  • bvseo_cps, prod_bvqa, vn_cps_3.1.6
  • cp_1, bvpage1
  • co_hasquestionsanswers, tq_2
  • loc_en_US, sid_120-840, PRD, sort_recentQuestionsFirst
  • clientName_PartsExpressInternational
Parts Express FacebookParts Express TwitterParts Express YouTubeParts Express PinterestParts Express SpotifyParts Express Instagram
Live Chat Software