Print Page - Purpose of this second cap on Pastyface power input?

Title: Purpose of this second cap on Pastyface power input?
Post by: EBRAddict on April 24, 2015, 12:06:02 AM

(http://i.imgur.com/NBPb0sh.jpg)

What is the purpose of film capacitor C9 (circled in red) on the Pastyface power input? I understand what everything else does (mostly), and C9 isn't part of the basic inverter layout in the data sheet. I searched but didn't see anything.

Title: Re: Purpose of this second cap on Pastyface power input?
Post by: midwayfair on April 24, 2015, 12:18:03 AM

film caps have lower ESR and are better at filtering high frequencies than electrolytic capacitors. It makes the power filtering better.

Title: Re: Purpose of this second cap on Pastyface power input?
Post by: EBRAddict on April 24, 2015, 12:54:24 AM

Thanks! I'm getting a tinnitus-grade squeal on the audio path when using the inverter vs. a battery so I wanted to figure out what everything did.

ETA: I see I didn't connect pin 1 per the schematic (I'm on a breadboard). Leaving it open = 10kHz switching frequency (tinnitus!), putting it to V+ sets the switching frequency to 45kHz, which coincidentally is just above the sampling frequency of many ADC.

madbeanpedals::forum

Projects => Tech Help - Projects Page => Topic started by: EBRAddict on April 24, 2015, 12:06:02 AM