Customer Reviews

Mastech HY1803D VARIABLE DC POWER SUPPLY

5 star:		(14)
4 star:		(4)
3 star:		(0)
2 star:		(0)
1 star:		(1)

 

 

The two most important things about this power supply are:
(1) The single adjustment knobs - 1 for voltage, 1 for amperage - are sufficient for both fine and coarse adjustments. With a little patience its easy to adjust by 1/100th. 1/10th or greater adjustments are mostly effortless.
(2) The output reading on the display is correct. I spent about 20 minutes when this first arrived comparing voltage and amperage output with a multimeter for the entire range that this power supply supports. All values were within 0.01 of the reading on the display (*note: I was hoping for 0.5 or better, so the accuracy that I found was a pleasant surprise).

I'm starting to get back into electronics hacking after a long hiatus, and this is a good tool for that purpose.

It arrived with the feet punched through the single wall cardboard box, and sawdust or dirt or something on the feet and bottom inside the plastic bag. It's clear they cut every corner they could to keep costs down, but if you know that going into it, I think this is a good deal.

I tested it out by hooking up a couple of 500 watt lights, and it delivered 18.8V and 3.1A, so it meets the specs. I heard only one relay click at about 9V, which means that it uses only two taps from the transformer... Other power supplies click a few times or more; more taps would make it waste less power throughout the range and run cooler, but if you use it infrequently wasting a bit of AC is not a big deal.

The meters seems decently accurate; my fluke 189 said 18.64V when it said 18.8V. The fluke said 3.077A when the mastech said 3.11A.

I'm not sure about the ripple though. I put the probe of my new Instek 1062a digital storage oscilloscope onto the banana clip outputs, and it measured approx 2mVpp ripple (varied from about 1.6mVpp to 2.4mVpp, mostly staying above 2mVpp). This is higher than the rated 0.5mV But when I tried switching between the 1x and 10x settings of the probe the measured ripple didn't change nor did waveform ripple that I saw on the screen, so there's something weird about my measuring setup; the 2V test signal on the oscilloscope at 1X did change to a 200mV signal with the 10X setting. I'm a beginner at using my DSO so take this with a grain of salt and if anyone can explain how to get a more reliable ripple measurement please tell me.

I did try powering a cheap old radio shack amplifier (277-1008c) with it, and didn't hear any more noise or hum than when powering it from 9V battery, so the ripple so far isn't an issue for me.

The binding posts are extremely cheesy; there's no hole in the posts so you have to wrap a long section of wire around the post, and there's only a very small contact area on the post base, making bare-wire connections not very practical. I think using banana plugs or perhaps spade connectors is the way to go with this. Probably not a bad idea to use a banana to binding post converter for bare wire connections, which you can easily unplug during power on to avoid any spikes from frying your circuits.

I agree with other posters that the coarse adjustment dials are sufficient, and I found it easy to adjust the voltage or current to within practical tolerances. I did find that the Voltage dial tends to cover up the "Voltage" label when this is on a tabletop, so I got confused and thought the Current label above it applied to the Voltage dial. Newbie mistake; I'll probably attach my own labels to make sure I don't get them confused. It would be nice to have backlights for the LCDs but they are readable enough in normal room light.

Overall, this seems like the Ford Escort of power supplies: Good enough to get the job done, but without any luxury or frills.

The current display shows how much current is being passed. The voltage shows how much voltage is being applied. It feels solid, the knobs are perfect for fine tuning. This product does exactly what it says, and very well.

Looking for a power supply with variable voltage and amperage, I found this. It offers separate controls for both voltage and amperage, allowing for a multitude of uses. I use it to test small motors and fans, and just to play around with equipment. Finding a supply that won't break the bank is a challenge in itself, and most voltage and amperage variable supplies are $200 and up. If you only need power within the 0-18v and 0-3amp range, then this should be a good match. Banana plugs fit right into the sockets, so you can use test leads or alligator clips. The positive and negative terminals also screw in and out, so you can attach wires via other means as well. The display is LED lit, and looks very nice when on. The only thing I would improve on the supply is the power cord connection, which doesn't seem to want to insert all the way in the back. A hard push will allow it to work, however. I recommend getting some test leads and banana to alligator leads as well, since this doesn't come with any.

Edit 1/23/11. When moving this supply, I heard a rattling inside. I opened it up, and found a plastic piece broken off of the transformer, so additional wires could be connected to the windings. This is not a critical piece to operation, but it would have been nice if it was removed at the factory.

Unit was non-functional when it arrived. LEDs worked but could not adjust anything with the dials. Opened case and found one of the large connectors was unplugged. The unit now works just fine but is a bit touchy as I have seen others mention. The instructions are somewhat confusing, but not long enough to confuse one for long.

It's not that the unit is defective now, it just feels a bit cheap.

Actually, this little power supply does everything I need. The voltage knob is sensitive enough so that a fine voltage adjustment knob is not necessary. This is an excellent power supply for digital work where I only need 5 volts.

This device is not properly grounded. It is not floating and it is not tied to earth ground. Instead, both the case screws and negative terminal are +22V referenced to earth ground. Connecting an oscilloscope ground clip to the negative terminal was enough to create a big spark and fry some components. Thankfully, Amazon was accepting of the return and I got the HY3005D instead. The HY3005D, though probably made by the same company, is able to be connected to earth ground without causing a short.

First, the unit had a reassuring weight to it. That says little about quality, but I was comforted.

The unit is highly accurate, certainly within .1 volts. It was nice to find my DVM and the power supply in such good agreement.

There was some slight ripple, ranging from 20 mV to around 160 mV, depending on the selected voltage. At most this was around 0.8%, nothing to get too worked up over.

The selected voltage remained stable. By this I mean that once I selected a voltage, it stayed there. It didn't drift as the unit warmed up, didn't change when I turned the thing off and then on again.

There were no frills to this unit. It gives you well-regulated and accurate power. If that's all you need, then this is a great little power supply.

My only regret has been not getting this sooner. Small and compact but has large LCD displays that can be clearly seen and are well back lit(the photo doesn't really show it). Very accurate and makes prototyping and testing much easier and is safer as the current limit protects the circuits that are being worked on. More than worth the money!

I needed an "electroplating machine" and this little power supply is just that! This little unit is sold through the jewelry supply catalog for plating, and it costs considerably more from the jewelry supply company. I ordered through Amazon, saved a few bucks, and now have shiny new nickle plated thingamajigs!