Struggling to understand a few capacitors on Nigels tuts

[mr Clauds]

Hey again guys

I hope i'm not becoming a nuisance, but ive searched all over and cant figure this out...

I understand capacitors, and it always seemed to me they need to be grounded to work (except for coupling), but im not understanding the capacitor C3?

I was under the impression that a charge would run up the one leg of the capacitor and then move back down the same leg introducing current into circuit again, and that the other leg simply caused the inbalance forcing charge to store?

Pin 2 (v+) is attached to +ve side of capacitor, pin 16 (Vcc) and 5v to negative side?
I thought the cathode should be grounded?
How is this capacitor working differently than the normal way?


Thanks for your patience...

**broken link removed**

 

[Nigel Goodwin]

Well firstly, it's not 'my' circuit, it's basically taken from the datasheet.

But it's a 'charge pump', think of the capacitors as buckets of electricity, been carried up and emptied into a larger bucket.

For a simple 'example' imagine another capacitor C6 in parallel with C5, let it charge up and then remove the capacitor, and reconnect it with it's -ve end to the +ve of C5. C5 will have 5V on it, but C6 will have that 5V plus it's own 5V, making 10V on C6. That's crudely what the chip does.

 

[Mike - K8LH]

Google "voltage doubler" for some additional background information.

Regards, Mike

 

[mr Clauds]

Thanks guys, I was searching on coupling and decoupling and capacitors and couldn't find anything, but now that i've used charge pump and voltage doubler, I've been able to learn about it...

Thanks
Clauds

 

[Mike - K8LH]

You're welcome Sir.

Have fun. Cheerful regards, Mike