HP / Agilent / Keysight · Bench power supply · From c.1995
The E3631A is the triple-output bench supply HP added in the mid-1990s, and it carried on through the Agilent years and into Keysight's. You get three supplies in one box, 0 to 6 V at 5 A and a pair of 25 V outputs at 1 A, positive and negative, which can track each other for op-amp and split-rail work. HP isolated the 6 V output from the 25 V pair to keep interference between circuits under test to a minimum. It's a linear supply with 0.01% load and line regulation, and the vacuum-fluorescent display shows voltage and current for one output at a time. GPIB and RS-232 are both standard and it speaks SCPI. Keysight now names the E36311A and E36312A as replacements. A unit set up for 230 V or 100 V just needs the rear selector turned and the right fuse fitted.
Options and accessories
Check the listing photos and the rear panel against this list, and ask the seller about anything you can’t see. A missing option or probe should come off the price.
The supply runs a self-test at power-on and lights an ERROR annunciator if something fails, and its status register even has a bit for a fan fault, so listen to the fan. Keysight warns that counterfeits of this or closely related products have been found.
New to used bench gear? How to check used test equipment covers self-tests, fuses, the voltage selector and shipping, and what “calibrated” means in a listing.
Buying guide
We'd buy jayhoehlinc's E3631A titled tested and working at $461 delivered, inside the $340–575 band, from a US test-equipment dealer whose photo shows it on and reading. There are at least 149 for sale, and plain used units here ask about $260–495 delivered, while esssurplus's no-bid auction at $116 will climb. Ask for a short video of it switching on with no ERROR annunciator, a meter on each of the +6 V, +25 V and -25 V outputs, and the fan's sound after a few minutes. Option 0E3 or 0E9 in a title means it left the factory set for 230 V or 100 V, so turn the rear selector and fit the right fuse before you plug it in. Skip the listing whose watermarked photo appears under two accounts, and the $1,254 one at about 3.1 times the median.
$116.30est. delivered
The lowest price here, esssurplus's no-bid auction at $116 delivered, and it will climb. The photo shows it on and reading OUTPUT OFF, but it isn't titled tested, so stop well short of the $461 tested unit.
HP Agilent Keysight E3631A Triple Output DC Power Supply (+-25V/1A, 6V/5A)
$460.88est. delivered
Titled tested and working at $461 delivered, inside the band, from jayhoehlinc, a US test-equipment dealer. The photo shows it on and reading, and ask for a meter on all three outputs.
Agilent E3631A Triple Output Power Supply ±25V 80W #15 Tested and Working
$460.88est. delivered
The easy first buy, a US dealer's unit titled tested and working, with shipping quoted. Ask how the fan sounds after a few minutes on.
Agilent E3631A Triple Output Power Supply ±25V 80W #15 Tested and Working
Delivered prices include shipping as eBay quoted it to a US address on Oct 14, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Snapshot
Checked . Some may have sold.
Delivered prices include shipping as eBay quoted it to a US address on Oct 14, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Used$116.30est. delivered
$49.99 + $66.31 shipping
Auction · no bids yet · ends in 6d 17h
Good buy
No bids yet, so it will climb. Photo shows it on, reading OUTPUT OFF.
Seller: esssurplus
99.8% positive
Used$460.88est. delivered
$349.95 + $110.93 shipping
Buy It Now$349.95
Good buy
Titled tested and working; photo shows it on and reading. US dealer.
Seller: jayhoehlinc
100% positive
Used$261.47est. delivered
$210.05 + $51.42 shipping
Buy It Now$210.05
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Our take
Not titled tested. Ships from Canada.
Seller: electronic_dist_intl
100% positive
Used$398.00est. delivered
$249.00 + $149.00 shipping
Buy It Now$249.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Our take
Option 0E3, so set for 230 V. Ships from Israel; photo shows it on.
Seller: katiil3
100% positive
Used$494.99delivered
$494.99 · free shipping
Buy It Now$494.99
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Our take
US dealer, free shipping. Not titled tested.
Seller: maverickindustrialsales
100% positive
Used$685.00est. delivered
$650.00 + $35.00 shipping
Buy It Now$650.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Our take
Titled OEM tested, above the band. US seller.
Seller: dfwforsale
100% positive
Used$384.00est. delivered
$314.00 + $70.00 shipping
Buy It Now$314.00
Check the seller
Same photo as a perfect-instruments listing, under a FUMISO watermark. Ships from China.
Seller: good-instruments
100% positive
Used$1,254.00delivered
$1,254.00 · free shipping
Buy It Now$1,254.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Priced high
About 3.1 times the median. Ships from Hong Kong.
Seller: indust61
100% positive
Prices change daily. The live eBay search shows everything listed now, including anything new since Oct 14, 2026.
See every listing on eBay ↗eBay search
HP / Agilent / Keysight
Multimeter$410–$575 typical ask
HP / Agilent / Keysight
Multimeter$1,275–$1,625 typical ask
Keithley
SourceMeter$3,700–$4,950 typical ask