capacitor questions

[justwantin]

G'day

I have been working at creating a pcb from the attached circuit. I've been running something similar using LM317s for several years with wall warts at higher voltages but this is intended to run off standard 5V cell phone chargers and use an LM3940 to drop voltage down to 3.3 to the PIC12F675 just to be safe.

My stanadard practice has been to use a 100n ceramic bypass capacitor in front of the PIC12F675 but would it be necessary in this circuit since I already have a 33uF capacitor between the LM3940and the microchip?

Also is there any problem created by placing the .47uF cap (C1) before I take +5V for the LEDs instead of after it.? My apologies if my terminology is not coreect.

 

[ronv]

I would keep the 100 nfd ceramic just for its high frequency response. C1 should be close to the regulator. The 5 volts for the LEDs from anywhere.

 

[justwantin]

Thanks, that was what I was inclined towards on the 100nf I wasn't at all sure about C1.