Author Topic: EEVblog #315 - Korad KA3005P Review/FAIL  (Read 143016 times)

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Offline GoneTomorrow

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #325 on: September 01, 2017, 12:06:43 PM »
Additional to that the fan rattles at idle.

Put a 50uF electro capacitor across the fan, it's caused by a really coarse PWM. Smoothing with a cap stops the rattling.
 
The following users thanked this post: alexjx, dorin

Offline jameson

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #326 on: November 06, 2017, 03:16:28 AM »
Hello! I have the same version of Korad as described by Almamater. Voltage when output is off is 10 mV. The minimum value that was obtained after calibrating is 2 mV. Is it normal? What is the voltage when ouput is off on your power supplies?
 

Offline Andreas

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #327 on: November 06, 2017, 03:46:05 AM »
Hello,

what do you expect?
Each power transistor has leakage currents in the order of some 100uA or even mA.
A 30V/5A power supply is neither intended for 2mA LEDs nor 1.5 V logic supplies.
Would be the same if you use a 20 pound sledge hammer for a drawing pin.

Here "output off" means  4.7 mV or 12.9 mA leakage current.
Zero voltage, output on = 9.5 mV or 26 mA

Accuracy spec is 0.5% (of 30V)  + 20 mV which means up to 170 mV total error.
similarly current 0.5% (of 5A) + 10 mA which means up to 35mA current error.
So your device is well within spec.

With best regards

Andreas

 

Offline jameson

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Re: EEVblog #315 - Korad KA3005P Review/FAIL
« Reply #328 on: November 06, 2017, 05:41:35 AM »
About the one I thought, but expect that the leakage current will be less. I have not found out what it is transistors are in my Korad.
In any case thank you for a comprehensive reply.
 


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