Basic DC Filter

[SimpleJoe]

Recently i bought a couple of DC - DC converters to use as a power supply (specifically 2x these: http://www.banggood.com/DP30V3A-NC-...Module-Constant-Voltage-Current-p-993033.html)
while using them to power a set of bluetooth speakers that i built i found that they output a very rough voltage as it just kept flicking the relay. my question is, is fixing this as simple as putting a capacitor on the output or will that somehow mess up its voltage measuring? also what size and voltage rating (it only has a 24v input so im assuming something larger than that) capacitor should i add?

Thanks in advanced for any help ,
SimpleJoe

 

[Harald Kapp]

You may simply need to set up the supply differently. Note that these are sold as "constant voltage current" supplies. Which most likely means (my interpretation of the supposedly English description) that you can use it either as a constant voltage source with currrent limiting (your application) or cionstant current mode with voltage limitation (not relevant here).

Set the output voltage to the desired nominal value.
Set the current to a value a bit higher than the nominal operating current of your speakers.
No additional capacitors should be required. If you still want to add some, use electrolytic capacitors with a rated voltage at least 20% over the nominal voltage you are using them (better yet: >=50%). As a rule of thumb use 1000µF per 1A of operating current. Note that the "power supply" may behave awkward if it is not designed to cope with highly capacitive loads.

 

[SimpleJoe]

i had set the controller as you had said (about 20v and 1amp output) yet it still flickered when turned on, this is what made me think that there was little to no voltage smoothing built into the controller. so if i put a 3000µF cap on the output (in parallel or series BTW?) it should handle up to the 3 amp max, will a 3000µF also work at lower voltages/amperages?

 

[Harald Kapp]

i had set the controller as you had said (about 20v and 1amp output) yet it still flickered when turned on

A good sign that this controller is crap.

(in parallel or series BTW?)

For DC in parallel.

will a 3000µF also work at lower voltages/amperages?

Will work fine with lower voltage/current, not well with higher voltage/current.

 

[SimpleJoe]

Yeah, i had got the controllers at less than half price, i always knew they were going to be sketchy at best but all i needed was a CV CC converter for less than the price of a professional lab power supply with 2 channels.

But thank you for all of you're help so far

SimpleJoe