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Topic: smooth 0-10v output (Read 1 time) previous topic - next topic

Joes

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

retrolefty

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

Lefty

Joes


Joes

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/

Docedison

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
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MarkT

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.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

akis31

i am doing the same project, i want to control a dimmable ballast,
is this circuit working? could you share the schematic please?

raschemmel

Are you planning to use an RC LP filter between the arduino and the op amp non-inverting amplifier
circuit ?
Arduino UNOs, Pro-Minis, ATMega328, ATtiny85, LCDs, MCP4162, keypads,<br />DS18B20s,74c922,nRF24L01, RS232, SD card, RC fixed wing, quadcopter

akis31

i have already an Lm 358n and an Lm 741, i am thinking of using two 10k res as Rf and Rin connected to the invrerting input and a 22k res and 0,47u cap at the non-inverting input.
But reading older posts they say that using a simple npn transistor can do the same job.

akis31

any other idea or suggestion?

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