Author Topic: New Benchtop PSU not displaying current ...  (Read 1598 times)

0 Members and 1 Guest are viewing this topic.

Offline KilroywashereTopic starter

  • Regular Contributor
  • *
  • Posts: 96
  • Country: ca
  • He has the stink of oil and electric circuitry...
New Benchtop PSU not displaying current ...
« on: November 24, 2017, 01:18:07 am »
Hey, I just got the STP3005H SKYTOP POWER supply . I  turn it on and it does not display current i turn the pots and nothing no 0 to 5 amps adjust..... However if i hook up a battery  3.4 v i can adjust it lower  till it shuts the thing down ( not off just zeros it out)


Is this normal in a cheap power supply???


Do you need more info or some pics?


Is this damn thing broken? or do i not know how to use it?
He is part of the dead...he has no place here. He has the stink of oil and electric circuitry about him. He is obsolete...
 

Offline Mr.B

  • Supporter
  • ****
  • Posts: 1237
  • Country: nz
Re: New Benchtop PSU not displaying current ...
« Reply #1 on: November 24, 2017, 01:41:26 am »
I cannot seem to find an instruction manual anywhere on the interwebs for it.
However, usually cheap supplies such as this require the following:

Set the voltage to your desired working voltage. e.g. 5.0V
Turn the current knob(s) down to zero.
Short out the pos and neg output of the supply.
Increase the current knob(s) until the desired current limit is displayed. e.g. 0.1A
Remove the short across the output.
The power supply should now supply 5Vdc up until it current limits at 100mA (0.1A)
While supplying the 5Vdc it will show you how much current is being drawn.
I approach the thinking of all of my posts using AI in the first instance. (Awkward Irregularity)
 
The following users thanked this post: Kilroywashere

Offline jcw0752

  • Contributor
  • Posts: 35
  • Country: us
Re: New Benchtop PSU not displaying current ...
« Reply #2 on: November 24, 2017, 04:53:40 am »
Hi,
You do not say anything about adding a load to the output. If you have just turned on the power supply without a load you will be able to adjust the voltage but since there is no load the current will not adjust and will continue to show zero regardless of where the current adjustment is set.

John
 
The following users thanked this post: Kilroywashere

Offline Brumby

  • Supporter
  • ****
  • Posts: 12288
  • Country: au
Re: New Benchtop PSU not displaying current ...
« Reply #3 on: November 24, 2017, 05:53:38 am »
It would seem this supply only displays actual values - and not "set" values.

For volts, this is easy - because voltage does not depend on a load (unless it is excessive) - so you can set the volts with the supply and nothing else.

For current - not so.  You will need a load of some sort so that there is an actual current flow that can be displayed.
You do not say anything about adding a load to the output. If you have just turned on the power supply without a load you will be able to adjust the voltage but since there is no load the current will not adjust and will continue to show zero regardless of where the current adjustment is set.
Just so.

If you want to be able to pre-set the current limit, then this is how:
Set the voltage to your desired working voltage. e.g. 5.0V
Turn the current knob(s) down to zero.
Short out the pos and neg output of the supply.
Increase the current knob(s) until the desired current limit is displayed. e.g. 0.1A
Remove the short across the output.
The power supply should now supply 5Vdc up until it current limits at 100mA (0.1A)
While supplying the 5Vdc it will show you how much current is being drawn.
 
The following users thanked this post: Kilroywashere

Offline mcinque

  • Supporter
  • ****
  • Posts: 1129
  • Country: it
  • I know that I know nothing
Re: New Benchtop PSU not displaying current ...
« Reply #4 on: November 24, 2017, 07:09:45 pm »
It's a normal behavior for "non programmable" PSUs, you can always see the voltage but you will see the current only with a load connected.

As Mr.B said, in that PSUs you should set your desired current by shorting the leads and adjusting the maximum current value or leave it to the maximum if you don't want a specific current limiting.

It is not broken, you need just a little bit of practice like everyone approaching something new.
 
The following users thanked this post: Kilroywashere


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf