Products > Test Equipment
Siglent SPD3303D review
FrankBuss:
My short review of the SPD3303D:
The test in the video starts with a serious problem on channel 3, with the fixed voltages output: there are big voltage spikes (up to 7V), even with load, if you turn it on or off. And it overshoots, if you short the output. UPDATE: see here how to fix these problems.
But there were no problems on channel 1 and channel 2 and it can be even used for a hand drill.
I opened the case at the end of the video, but it is not a full teardown and very short, because I don't know much about analog electronics anyway.
Not shown in the video:
* one hour load test with 8 ohm on channel 1 and channel 2 each, and 2 ohm on channel 3. The fan starts, not too loud, and the power supply survived it
* if you want to use the PC software, you have to instal the NI environment first: http://joule.ni.com/nidu/cds/view/p/id/4230/lang/en (the registration doesn't need eMail confirmation, so enter what you want)
* I've tested the channel 3 a bit more, and on the 5V selection there is a voltage of 82mV when turned off, 48 mV for 3.3V and 46 mV for the 2.5V selection. Can be loaded with 2 ohms, still there.
* problem with "all on/off": if e.g. channel 1 is on, channel 2 and 3 are off, and then I press "all on/off", it turns all channels on. I would expect that it turns any channel off, which is on, but maybe it is just me who is surprised by this feature :)
* lock-key: in lock-mode, it is still possible to change the voltage from the PC
* parallel and series mode: in parallel mode, channel 1 and channel 2 are parallel (and available at the terminals at channel 1), for currents up to 6.4A, and in series mode channel 1 and channel 2 are linked in series (and available at the negative terminal of channel 1 and the positive terminal at channel 2), for voltages up to 64V. Unfortunately it is just a relay internally, the display doesn't sum the voltage or the current and it is the same, as if you would link it externally (which is possible, too, because the channels are all independent of each other)
* wave display: this shows a waveform of the voltage and current. Can be enabled individually for each channel. It is difficult to read, because there are no scale lines and it has no auto-scaling.As said in the video, my conclusion: the power supply is not perfect, but it is nice for the price and I would buy it again.
Discussion about my power resistors and some more ideas for cheap homebrew dummy loads:
https://www.eevblog.com/forum/testgear/power-resistor-dummy-load-for-psu-testing/
The stackable cables with banana plugs are from this eBay shop:
http://stores.ebay.de/chr
I'm not affiliated with this seller, but I have bought such cables from other sellers and they were very bad, with thin wires with an iron/copper alloy and not very solid plugs. So maybe this is useful, if someone wants to buy good cables.
High resolution photos:
logic board, left side
logic board, right side, far focus
logic board, right side, near focus
mains switch
regulator board, left side (there is some rust)
regulator board, right side
top view, back
top view, front
top view, left
top view, right
The mosfets on the heatsinks are IRFP150N. There are two of them on the right heatsink, but only one on the left heatsink, and looks like a temperature sensor is mounted instead on one heatsink. And there is another big 4 leg IC on each heatsink, which has no label (doesn't look like it was sanded, just mounted the wrong way on the heatsink). On the logic board the main microcontroller is a STM32F103. There are some PC817 photocouplers and some JQC-3FF relays.
Hydrawerk:
It's like... I do not need any color LCD, give me a simple PSU with no spikes and no other HW problems. I have heard good things about Statron PSU. http://www.statron.de/details/19
http://www.statron.de/details/306
I love the 1980's style. But yes, these PSUs are manufactured today.
FrankBuss:
I've used a Statron at a client, good quality, I like the multi-turn potentiometer for the voltage. But you can't control it from a PC, which is useful for some applications, if you write your own programs to control and monitor it.
For example once I helped working on a watchdog problem, where once in a while a device reseted right at boot. To see if the problem was fixed, a complicated setup was built, with an external relay to switch a power supply. Would be just a few lines of code with a power supply with USB, and you can detect a successful booting by reading the current consumption with one of the USB commands, or by combining the code with which controls the power supply with some readings from the serial port of the DUT.
Zbig:
--- Quote from: FrankBuss on September 07, 2013, 11:25:12 pm ---[..] parallel and series mode: in parallel mode, channel 1 and channel 2 are parallel (and available at the terminals at channel 1), for currents up to 6.4A, and in series mode channel 1 and channel 2 are linked in series (and available at the negative terminal of channel 1 and the positive terminal at channel 2), for voltages up to 64V. Unfortunately it is just a relay internally, the display doesn't sum the voltage or the current and it is the same, as if you would link it externally (which is possible, too, because the channels are all independent of each other)[..]
--- End quote ---
It's not exactly just a relay. The channels are actually being put in tracking mode by software so their control loop controls are tied together (with "slave" following the "master"). It wouldn't work that way if the firmware wasn't "aware" of the serial/parallel mode you're currently in. It's only the actual summing of readings what it doesn't do for you.
george graves:
This (I hope) isn't a silly question ..... but how hard can it be to design a PS WITHOUT a turn on spike?!?!?!?
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