# Tag Info

Accepted

### How to identify filter behaviour without memorizing different topologies

Look at the extremes. DC and very high frequencies. For DC you can remove the capacitors and short the inductors. For high frequencies you can short the capacitors and remove the inductors. By looking ...
• 8,195

### Why do we need R1 in a non-inverting op-amp?

It's for biasing the (+) input. If it's not there, then the bias current of the op-amp will have no where to go and the voltage at that node will drift. This RC combination forms a bit of a high-pass ...
• 3,790
Accepted

### Design constraints when dealing with very high resistances in op-amp's feedback loop

I used to do condenser microphone stuff professionally, which was very much this kind of thing (10G ohms with maybe a 30pF source). Cleanliness is VITAL, a bit of skin oil in the wrong place and you ...
• 17.5k

### How to calculate values for decoupling capacitors

Basically you want something close enough to the pin that at the edge rates in play the bounce is not too bad, and then something further away with (possibly) enough ESR to damp everything to keep the ...
• 17.5k
Accepted

### What is the purpose of the 250uF capacitor in the LM386 circuit?

Yes, 470uF will work fine, it will just extend the bass response somewhat. It's a coupling capacitor (or a blocking capacitor, to block DC, if you prefer). The 10R + 50nF is a "Zobel Network", ...
• 393k
The resolution to the conundrum is that there really is no conundrum. Your input, a step function, has infinite dc component (its Laplace Transform, $1/s$, goes to infinity as $s\rightarrow 0$). ...