Leads on 25v 2200uf caps?

[SIDvicious]

I have a DIY synth project I am working on. The power supply is a 9v AC/5V DC supply (used for powering c64 SID chips).

The 9v rail has a full wave bridge rectifier with two 2200uf caps in series right after it.

The designer of the circuit specified 25v caps in the BOM. He stated the reason is to expect double the voltage after the rectifier but says 16v "should be fine".

So myself being OCD...I want to be safe and use 25v caps but the vias for the caps are too tiny for the leads of the panasonic 25v caps I have. And, obviously, I don't want to use bad caps.

Would it be ill advised to strip the leads thinner? Or, does anybody have any knowledge of 25v rated caps with thinner leads?

[mariushm]

Re: Leads on 25v 2200uf caps?

Rectified AC voltage results in a DC voltage with a peak of 1.414 x Vac, minus the losses in he rectifier, of about 1.8-2v . For 9v AC , you have 1.414 x 9v -2v = 11v
Some transformers, especially low VA ones as the ones, could actually output 10-30% more than the value listed when idle or when device doesn't use any power, so you could actually have 10-11v AC, which would make the voltage on the capacitors close to 16v, somewhere around 14v DC.

So yeah, 16v rated caps should work, but probably when that thing was made, considering the technology and quality of capacitors back then, maybe it made more sense to use 25v rated capacitors.

I would use bits of leads of other capacitors to solder them on board and leave about half a cm above the pcb and then solder the leads of the capacitor to those small leads. Then, use some hot glue to lock the new capacitor in place.

[SIDvicious]

Re: Leads on 25v 2200uf caps?

I would use bits of leads of other capacitors to solder them on board and leave about half a cm above the pcb and then solder the leads of the capacitor to those small leads. Then, use some hot glue to lock the new capacitor in place.

Hey thanks a lot for the reply.

I actually feel safer using 16v now...I might just go with that.

But your suggestion for the leads was very helpful. Don't know why I didn't think of that earlier! I can go either way if I choose now.

[euromatlox]

Re: Leads on 25v 2200uf caps?

The 9v rail has a full wave bridge rectifier with two 2200uf caps in series right after it.

In series ? Or parallel (which is more usual) ?

http://electronics.stackexchange.com...rs-in-parallel

If parallel, the total capacitance is then 2x2200uF = 4400uF. There are reasons (limited space etc.) for use two 2200uF instead of one 3900uF or bigger cap.

[SIDvicious]

Re: Leads on 25v 2200uf caps?

In series ? Or parallel (which is more usual) ?

http://electronics.stackexchange.com...rs-in-parallel

If parallel, the total capacitance is then 2x2200uF = 4400uF. There are reasons (limited space etc.) for use two 2200uF instead of one 3900uF or bigger cap.

Yes, parallel..I always confuse the 2.

[Mint Waxed]

Re: Leads on 25v 2200uf caps?

I have a DIY synth project I am working on. The power supply is a 9v AC/5V DC supply (used for powering c64 SID chips).

The 9v rail has a full wave bridge rectifier with two 2200uf caps in series right after it.

The designer of the circuit specified 25v caps in the BOM. He stated the reason is to expect double the voltage after the rectifier but says 16v "should be fine".

So myself being OCD...I want to be safe and use 25v caps but the vias for the caps are too tiny for the leads of the panasonic 25v caps I have. And, obviously, I don't want to use bad caps.

Would it be ill advised to strip the leads thinner? Or, does anybody have any knowledge of 25v rated caps with thinner leads?

If I wanted to use higher voltage cap (provided there was room for them on the PC board) and the leads would not fit through the mounting holes, I would drill them out to make a larger diameter. To do this, you need a set of ultra sharp PC board drill bits and a miniature chuck that can hold them. The miniature chuck is then placed into the chuck of a normal sized drill. Then, you will have to drill into the foil side of the board so the bit don't lift the trace off the board as it pushes through. Once finished, your larger lead part should fit. This assumes of course that there is room for the part and the lead spacing if radial is correct.