Author Topic: Bench power supply suggestions [intermediate level, undergraduate EE]  (Read 5074 times)

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Offline nctnico

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Re: Bench power supply suggestions [intermediate level, undergraduate EE]
« Reply #50 on: September 24, 2019, 08:13:15 am »
Overall, I much prefer the DP832(A) but it is bigger and heavier if that's an issue for you.

The old color monitors (think Sony MultiSync CRT type) and linear power supplies share one thing in common:  You buy quality by the pound.  A heavier supply is better than a lighter supply. For the PS, you're buying a more robust transformer and more heatsinking.  The weigh difference isn't in the PCBs themselves, it's in the metal stuff.  More weight is good!
No. Think about (efficient) torroidal transformer versus an old style one. Also more weight can mean cheaper steel enclosure instead of aluminium. Either way heavy equipment is a nuisance to move around.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline GerryR

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Re: Bench power supply suggestions [intermediate level, undergraduate EE]
« Reply #51 on: September 24, 2019, 11:28:53 am »
The older "stuff" is straight-forward and easier to use.  I would gather that most of the features of these newer supplies, very few people will use, but the displays look pretty.  I don't care what the supply "says" the output is, or to how many digits, I always check the outputs with a calibrated multi-meter before hooking up to a circuit; it's just good practice.  I think there is a tendency for some to go for appearance as much as anything else.  Features like "sense" inputs on a bench supply(??), maybe if your test setup is across the room, but not on a bench.  Just measure the voltage at the destination and tweak the supply, if necessary.  CC / CV definitely a must and independent grounds, very convenient.  Weight is good, if for nothing else but to keep the unit from moving when you go to change a control setting.  (I have a newer ARB that slides away from my hand when I go to depress a button; most annoying.  My older, less capable ARB would'nt do that.  There is a lot to be said for the industrially hardened equipment instead of what is being passed off today.  Just my $.02.
Still learning; good judgment comes from experience, which comes from bad judgment!!
 

Offline nctnico

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Re: Bench power supply suggestions [intermediate level, undergraduate EE]
« Reply #52 on: September 24, 2019, 01:05:47 pm »
The older "stuff" is straight-forward and easier to use.  I would gather that most of the features of these newer supplies, very few people will use, but the displays look pretty.  I don't care what the supply "says" the output is, or to how many digits, I always check the outputs with a calibrated multi-meter before hooking up to a circuit; it's just good practice.
Not in today's world. For older PSUs with 2.5 digit readouts for voltage and current or a scale you'd need to check the output voltages. But nowadays the higher end bench power supplies come with 4.5 digits DMMs built-in for both current and voltage. Especially the current is a good one because unlike a DMM a power supply doesn't have any extra burden voltage. Also you may want to change the voltage in between or use the PSU the next day again. Do you really want to pull out a DMM and check every output voltage and current of a power supply? It is a real nuisance to have to work that way.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline 2N3055

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Re: Bench power supply suggestions [intermediate level, undergraduate EE]
« Reply #53 on: September 24, 2019, 01:15:11 pm »
The older "stuff" is straight-forward and easier to use.  I would gather that most of the features of these newer supplies, very few people will use, but the displays look pretty.  I don't care what the supply "says" the output is, or to how many digits, I always check the outputs with a calibrated multi-meter before hooking up to a circuit; it's just good practice.
Not in today's world. For older PSUs with 2.5 digit readouts for voltage and current or a scale you'd need to check the output voltages. But nowadays the higher end bench power supplies come with 4.5 digits DMMs built-in for both current and voltage. Especially the current is a good one because unlike a DMM a power supply doesn't have any extra burden voltage. Also you may want to change the voltage in between or use the PSU the next day again. Do you really want to pull out a DMM and check every output voltage and current of a power supply? It is a real nuisance to have to work that way.

To be more precise, if you have something like DP831/832 you get 3 x voltage and current and power. That is 9 measurements that are just there with no effort.
I use my DP831 ALL the time just because of that.. And resolution is enough that you don't need anything else most of the time.
And Keysight 36300 and 36100 series have low range current mode that is good enough to measure low power devices with full range scale range of several mA...

 
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