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I'm pretty new to electronics, and while exploring the web I came across this circuit for a 180v Nixie tube power supply. http://www.electronics-lab.com/project/hv-nixie-dc-dc-switching-power-supply/ (Schematic is here http://www.electronics-lab.com/wp-content/uploads/2015/03/schematic38.png). Most of the components are just capacitor of various type between Ground and Power (12v and 180v). What is their purpose? Would the circuit still work if I remove some or all of them?

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The circuit in question redrawn to make clearer: -

enter image description here

  • C1 - bulk low frequency reservoir capacitor
  • C2 - high frequency reservoir capacitor
  • C3 - reference supply decoupler
  • C4 - bulk low frequency output reservoir capacitor
  • C5 - high frequency output reservoir capacitor

Remove any and you degrade performance. I can't tell you how much and I'm not getting into alternatives - do some googling and use the reference names I gave them. The fact that I can give them reference names must mean all are fairly important!

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The circuit is a simple boost-converter. The capacitors used in the circuit are decoupling capacitors. Please read up on power supply decoupling. It could save you a lot of headaches trying to figure out why something does not work properly.

The circuit would probably still work without the 100nF capacitors (C2 and C5), but I would certainly not recommend it! The circuit will be noisy and could radiate noise to other circuits.

C3 is used to decouple the internal reference voltage of the regulator. Without this capacitor the regulator will be unstable.

The larger electrolytic capacitors (C1 and C4) form the "bulk" capacitance. Removing these will make the switching regulator behave erratic.

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