I'm designing my active filters. Are there any things to consider when paralleling resistors or capacitors to get the wanted values?
I chose // resistors thinking of board layout. Maybe series is better ?
I chose // resistors thinking of board layout. Maybe series is better ?
I use parallel for both resistors and capacitors. I design for 3 of each, and I don't have to use links if I only use 1 or 2. Plus it's usually caps that give you a hard time on values, and paralleling lowers inductance and raises capacitance.
How accurately do you try to match your filters?
If my 24db LP worked out spot on 200Hz is it OK if the HP stages are say 197Hz and 203Hz ? or does that do something nasty to the signal (phase?)?
ie do I have to match the 2 stages closely to each other or can they be used as above to average out?
PS. Roughly how much is a capacitance meter?
If my 24db LP worked out spot on 200Hz is it OK if the HP stages are say 197Hz and 203Hz ? or does that do something nasty to the signal (phase?)?
ie do I have to match the 2 stages closely to each other or can they be used as above to average out?
PS. Roughly how much is a capacitance meter?
PEAK electronics manufacture a LCR meter, which costs £79.
http://www.peakelec.co.uk/acatalog/jz_lcr40.html
http://www.peakelec.co.uk/acatalog/jz_lcr40.html
A couple of Hz at 200Hz is absolutely nothing, it's 1% error. IMO there's no need to measure caps, but it can't hurt if you want to.
I use 1% resistors and 5% caps and always get perfectly good enough results. Paralleling caps also usually gains you better than 5% tolerance anyway due to stats, according to Doug Self. Whatever you use will be MANY times better than a passive crossover anyway.
I use 1% resistors and 5% caps and always get perfectly good enough results. Paralleling caps also usually gains you better than 5% tolerance anyway due to stats, according to Doug Self. Whatever you use will be MANY times better than a passive crossover anyway.
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