UV Light Meter Circuit (Analogue)

[Andytester]

Hi All, I'd like to make a very basic UV light meter to measure the output of UV florescent tubes as they warm up.
The Idea is that I would be able to see the output rise on the meter and know when the Tubes are warmed up.
I cant find a Schematic dedicated to UV but I'm guessing I could use a basic op amp amplifier with a UV photo Diode and somehow drive an analogue meter.
The unit doesn't need to be calibrated, just consistant. Its just to tell when the tubes are approaching their brightest so I don't waist the limited tube hours before I use them.

Any Idea if the attached circuit would work with my UV diode?

Any tips or hints would be appreciated as I'm not good at design but I can build most circuits.

 

[CDRIVE]

The circuit looks adequate but posting your UV Diode model might be prudent. Not having much experience with them I don't know if UV Diodes also respond to other light spectrums. If that's the case it would require an optical filter. The datasheet for your Diode would hopefully spec this.

Chris

Edit: Oops I just saw that you also posted the UV Diode datasheet! I'll read it now.

 

[Andytester]

Thanks for taking a look Chris.
I'm not too worried about visible light as the sensor Diode will be placed very close to the tubes in an unlit room so I think the sensor will be well saturated with 311nm UVB (Philips Narrowband TL/01)
It can probably be achieved with a simple transistor circuit but I've not got that far yet.

Andy

 

[CDRIVE]

Hi Andy. I read through your datasheet and it would appear you don't need an optical filter. On that note it's always advisable to breadboard the circuit prior to building and enclosing it. It reduces those "Oh sh!t" moments.

Keep us updated on your progress.

Good luck,
Chris

 

[Andytester]

Settled on this circuit in the end, it works fine and puts out about 2.5v next to a daylight Florescent tube. Now waiting for a better UV Diode as the original one has a response from UV right through to Infra red and may be influenced by the heat of the lamps. The next UV diode I'll try has a very narrow band and will only respond to UV. I changed C1 to 1nF to lower bandwidth, as its just an analogue light meter. Not tested circuit bandwidth.