Capacitors still kind of confuse me, and the terminology has me scratching my head. I understand what they do, but calculating them is still something I don't understand. When you say "next to" and IC, do you mean from the +5V, to ground?
Resistors I got, Capacitors frustrate me... Shane On Thu, Jul 21, 2011 at 4:16 AM, Nick <[email protected]> wrote: > Decoupling should be done EVERY time on EVERY chip - analogue or > digital - right adjacent to the supply pins. > > It costs pretty much nothing, and saves a whole bunch of trouble. Just > do it. > > Part of the need to do this is that chips today are much much faster > than they used to be, so where frequency response would roll off > before oscillation, nowadays even standard opamps can have GBWs in the > MHz to 10s of MHz range, and logic goes far far higher. > > On the analogue side, I'm currently restoring some Quad amps - the > amount of pure twaddle on the www about using loony opamps like the > OPA627 and much faster (in "audiophoolery" faster = better) class A > drivers & output stages - recipe for high-frequency instability - the > circuit were designed to use the inherent limits of the original > devices. > > Maybe I'll just spend 1000 bucks on some speaker cables and > unidirectional 99.99999% OFC internal cabling. Not. > > Nick > > On Jul 21, 9:50 am, jb-electronics <[email protected]> > wrote: > > Hi, > > > > > (2) Sprinkle capacitors across power and ground all over your circuit. > > > Preferably as close to the power and ground pins of each chip as > > > possible. Usually they're 0.1uf (100nf) ceramic capacitors. Some big > > > chips require you to use several near them, so read you datasheets. > > > Chips are fast. Very fast. They can either generate very brief short > > > circuits (in the ballpark of 10nS), and/or be susceptible to these > > > very short glitches on the power rails. > > > > I cannot stress enough how much pain this will spare you. I recently > > built a combined volt- and amperemeter with a 2x16 LCD readout on a > > rather small pcb, and I did point-to-point-wiring like I always do, and > > it did not want to work. Some weird oscillations at the volts ADC. The > > first thing I did was inserting a 100nF cap next to every (!) IC, and > > bam, problem solved. > > > > Jens > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To post to this group, send an email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/neonixie-l?hl=en-GB. > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
