EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: zapta on April 01, 2014, 02:41:00 pm
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I was in the market for some time for a home bench power supply, single output 20V, 1.5A, separate digital voltage/current displays (preferably adjusted with an encoder, not pots), quiet to the ear, reasonable quality, and reasonable form factor (that is, not one of those 19" monsters). I don't care about remote programming.
After looking around I thought that I found the one, a Korad KA3005D. It arrives yesterday, I was somewhat disappointed with the quality (it looks very nice in the pictures) but the show stopper for me was the loud fan, so the search continues.
My current candidates and my questions are:
1. A used HP E3611A - everything looks good and it does not have a fan (good) but it also does not have an output on/off button.
Q: Is not having an output on/off switch a problem? Is it safe to use the mains switch as output on/off? I expect to power cycle often and am not sure how safe it is to the power supply and what kind of voltage overshoots my boards will get.
http://www.home.agilent.com/en/pd-838244-pn-E3611A/30w-power-supply-20v-15a-or-35v-085a (http://www.home.agilent.com/en/pd-838244-pn-E3611A/30w-power-supply-20v-15a-or-35v-085a)
2. A new or a used Agilent U8001A DC - this one has an output on/of button (good) but has a fan.
Q: How loud is the fan? Does it start at all for low loads (1~3 watts)?
http://www.home.agilent.com/en/pd-1401523-pn-U8001A/dc-power-supply-30v-3a?nid=-35673.783963&cc=US&lc=eng (http://www.home.agilent.com/en/pd-1401523-pn-U8001A/dc-power-supply-30v-3a?nid=-35673.783963&cc=US&lc=eng)
Also, is there other power supplys I should consider? I am in the US and don't have a specific budget limit but would be nice to keep it under $300~400.
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Power Designs 2020B, quiet in more ways than audible :)
Even better is a HP 6114A
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I've had a E3611A as my goto power supply for 5+ years. It has been a rock solid performer and is of course fanless and quiet.
You can trim the front display to be more accurate, though the display is only 1 decimal on volts and 2 decimals for current. For a lot of my use I really would have liked one more decimal. I now run a DP1116A as my goto power supply (many of my designs now require >5A).
I also have several other E36** series HP supplies that I scored for free from a previous company I consulted at. They are great supplies within their power capabilities.
I never missed an on/off button, but then not having one to start with I got use to unplugging a lead and/or adjusting the current limit etc prior to powering up new prototypes etc. I wouldn't just cycle power since the ramp up time may become an issue depending on your load. You could always add an inline switch to your test lead if you need to cycle power a LOT.
One thing on the HP is that over time (years) I've seen the voltage/current range buttons 'crack' - a bit of superglue can take care of if caught early. I've seen 'used' units with missing buttons...
cheers,
george.
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I never missed an on/off button, but then not having one to start with I got use to unplugging a lead and/or adjusting the current limit etc prior to powering up new prototypes etc. I wouldn't just cycle power since the ramp up time may become an issue depending on your load. You could always add an inline switch to your test lead if you need to cycle power a LOT.
Thanks george, I think I can leave with plugging a banana plug in/out. I will got after the E3610A then since I typically work with lower voltages.
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Power Designs 2020B, quiet in more ways than audible :)
Even better is a HP 6114A
I guess both qualify as 'digital' ;)
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Not only digital but more accurate than most hand held DMM's so no need to check the voltage. Leave the meter on amps and you have dual readouts ;). If you look at the specs of the 6114 or 6115 you will see these put most other power supplies to shame.
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I have a HANTEK PPS2320A 3 Channel (240$ with shipping) on the way from China, can give a teardown and report upon arrivial..
http://www.aliexpress.com/snapshot/6045729873.html (http://www.aliexpress.com/snapshot/6045729873.html)
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http://www.ebay.com/itm/Power-Design-Inc-PDI-2020B-0-20VDC-0-2A-Precision-DC-Power-Supply-/141242050499 (http://www.ebay.com/itm/Power-Design-Inc-PDI-2020B-0-20VDC-0-2A-Precision-DC-Power-Supply-/141242050499)
broken meter but it might be a simple fix. you don't need the meter much other than for amps, and even that is not needed to be a functional psu.
there are some other 2020's out there ($150 for one of them). I dislike writing on the front or top but if you can overlook that, its a pretty good deal. the first 2 digits are the max voltage and 2nd two are the current, so 2020 is 20v and 2.0a max. not bad, really.
I have 4 or 5 PDI units and just don't need anymore (lol) but I highly recommend them!
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Not only digital but more accurate than most hand held DMM's so no need to check the voltage. Leave the meter on amps and you have dual readouts ;). If you look at the specs of the 6114 or 6115 you will see these put most other power supplies to shame.
+1 , heck, personally I don't call mine a power supply anymore, instead of a high power voltage & current "reference". >:D
The specification :
Voltage mode :
Load regulation : 0.0005% + 50uV
Line regulation : 0.0005% + 100uV
Ripple & noise : 40 uVrms/100uV p-p
Temp Co : 0.001% + 15uV
Drift (over 8 hours under load) : 0.0015% + 15uV
Transient recovery time : < 50uSec with 10mV of nominal output
Output impedance : 0.05 mOhm in series 3 uH inductor
Output voltage accuracy : 0.025% + 1mV
Current mode :
Load regulation : 0.01% + 500uA
Line regulation : 0.005% + 20uA
Ripple & noise : 200uA rms/1mA p-p
Temp Co : 0.02% + 25uA
Drift (over 8 hours under load) : 0.25% + 4mA
It's look can be deceiving.