Question about capacitors

[Djakkennaia]

Hello, I'm new to the forum. I am currently making a 110mW blue/violet laser diode. Some of you might be familiar with this as the PHR 803-T diode project. I chose to make my own circuit, just to give myself a little more challenge. In the instructions, it calls for a 10 microfarad 16 volt capacitor to act as buffer in case the start up current is too high. I was wondering if I could use a 10 microfarad 50 volt capacitor instead, since that is all I have at the moment that offers 10 microfarads. Dosen't the voltage rating just tell the maximum voltage than a capacitor can take? thanks in advance!

 

[lasersbee]

If the Capacity (microfarads) is the same you can use any
Capacitor voltage as long as it is not lower than the voltage
it will see..
A good rule of Thumb we use is Two times the max voltage
of the circuit.
For example on a 12VDC circuit we would use 25V rated
capacitors...

The only difference between a 50uF 16V cap and a 50uF 50V
cap is that the 50v cap will be larger...


Jerry

 

[random person]

If the Capacity (microfarads) is the same you can use any
Capacitor voltage as long as it is not lower than the voltage
it will see..

not for fast acting transients... low ESR is needed or else caps do not have to much of an affect. These transients depend on many things though so I guess its best to have a large electrolytic cap + a ceramic low ESR cap to cover both spectrum of transients. Classic input protection....

 

[lasersbee]

not for fast acting transients... low ESR is needed or else caps do not have to much of an affect. These transients depend on many things though so I guess its best to have a large electrolytic cap + a ceramic low ESR cap to cover both spectrum of transients. Classic input protection....

He is asking if he could use a 50v/10uF electrolytic instead of a 16V/10uF
electrolytic that is shown on the DDL schematic/drawing...
I still say YES....

Jerry

 

[Benm]

I would agree here. The LM317 datasheet does not call for any specific type of capacitor or ESR performance level, so most 10 uF capacitors would do nicely.

As long as size is not a problem you'll be fine with the 50 volt rated part.