RE: Technics SP 15 capacitors - manual discrepancy

Posted by flood2 (A) on January 19, 2017 at 02:18:52

In Reply to: Technics SP 15 capacitors - manual discrepancy posted by GregK on January 18, 2017 at 05:38:50:

The higher voltage rated caps will have a lower loss tangent (lower ESR). Normally a designer will choose a margin of at least 2x the actual voltage across the cap. So if the max voltage is say 15V, the designer would normally choose 35V.
For a given cap "model" if a designer has opted for the 50V version even the diagram shows 16V, he may be doing it because that particular brand requires him to use the 50V version to meet the ESR requirements.
The value for C303 and C304 will depend on what the purpose is. If they are smoothing caps at the output of a regulator, then they are for stability and the minimum value would be 10uF. The 100uF will give a slightly improved stability and reduced output ripple if the transient current draw rate is higher than the regulator can sustain without a larger reservoir but you may get more noise passing through - the lower values are better. What are they used for? Power supply decoupling?

General rule of thumb (which everyone else has already mentioned) just do a like for like replacement on what you see unless you understand the circuit enough to modify it. Even then, throwing in exotic low ESR caps can actually make things worse if the designer has fine tuned the design with a particular cap property in mind - case in point Oscon caps require a series resistor to limit the current as the peak current can exceed diode ratings if you are replacing a "normal" electrolytic with an Oscon!
Regards Anthony

"Beauty is Truth, Truth Beauty.." Keats

This post is made possible by the generous support of people like you and our sponsors:

Follow Ups Full Thread

Topic - Technics SP 15 capacitors - manual discrepancy - GregK 05:38:50 01/18/17 (9)

Thanks all for your valuable insight! - GregK 10:52:58 01/19/17 (2)

Digikey and Mouser - Lew 11:33:54 01/19/17 (1)

Thanks, Lew! I knew about Digikey... - GregK 12:22:13 01/19/17 (0)

RE: Technics SP 15 capacitors - manual discrepancy - flood2 02:18:52 01/19/17 (0)

RE: Technics SP 15 capacitors - manual discrepancy - Lew 07:23:10 01/18/17 (0)

RE: Technics SP 15 capacitors - manual discrepancy - Dave Garretson 07:06:29 01/18/17 (0)

RE: Technics SP 15 capacitors - manual discrepancy - Uncle Mike 07:00:56 01/18/17 (0)

RE: Technics SP 15 capacitors - manual discrepancy - EdAInWestOC 05:42:34 01/18/17 (1)

2nd! (nt) - Crazy Dave 10:40:32 01/18/17 (0)

Follow Ups

RE: Technics SP 15 capacitors - manual discrepancy - flood2 02:18:52 01/19/17 (0)

RE: Technics SP 15 capacitors - manual discrepancy

Post a Message!