LinuxMusicians

There's ##music-electronics on libera.chat.

I thought capacitors limited signals closer to DC, i.e. low frequencies, but I'm often wrong in life!

This seems like a good video on the topic, I'll watch it fully soon https://youtu.be/l-u8J-yh9ZA

One way of thinking about a capacitor is as a frequency dependent resistor. When dealing with AC instead of 'resistance' we say 'impedance'. At low frequencies a capacitor has a high impedance, and at high frequencies it has a low impedance.

DC is the lowest frequency, it's 0Hz, so at DC a capacitor looks like an open circuit. This is why there is often a capacitor on an audio input -- to block DC. 'DC coupled' inputs leave out the capacitor and these are important when using low frequency control signals.

At high frequencies a capacitor looks like a short circuit and this is why you see loads of capacitors on a motherboard. They connect the power supply rail to earth so that voltage spikes (high frequency) go to earth.