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[on:]

hi there im trying to convert my 0-5v pwm output of the arduino to a smooth 0-10v for a high frequency flourescent i come across this just wanted to make sure that this would work or if people have got better suggestions?

http://aartsite.nl/licht/o_5vhrfi.htm

[Reply #1 on:]

That circuit looks like a good and proper way to accomplish the task.

Lefty

[Reply #2 on:]

thanks 

[Reply #3 on:]

on that he is using a LM324 i dont need 4 lost of it, just 2 so will this be fine?
http://uk.rs-online.com/web/p/operational-amplifiers/0463145/

[Reply #4 on:]

Yeah, I do it's probably what was used originally, the 358 is a Very common Op-Amp. Made by almost everyone in the semiconductor business and there are several dozen others with the same pin-out with varying characteristics. Since the device is driving a transistor it is a current feedback loop. It is easy to misuse and if misused not perform with anything like expected. there is a hard limit of about 200 mA on that transistor and a power type will not perform either as with most op-amps the output drive current is limited so controlling a bigger transistor has it's issues. Good Luck.

Doc

[Reply #5 on:]

The only problem with that circuit might be stability - adding a 47pF capacitor between the opamp output and its inverting (-) input would cure that.

The issue is that the opamp feedback path has to go through a potentially slow component (transistor) and drive a capacitive load (C3) - this might introduce enough phase-lag to induce oscillations.  The small capacitor would provide a high-frequency lagless feedback path to quell such a tendancy without affecting low frequency behaviour.