Photodetector?

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wil
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Joined: Wed Oct 27, 2004 8:32 pm
Location: Chicago, IL

Photodetector?

Post by wil »

I am building a device for the detection of fluorescent light at various intensities (some at very low levels). The detector is a silicon photodiode photovoltaic with two leads. Data does not need to be collected more than once per second. Can you recommend a data logger? The ADC-10 seems suitable, but I am a life scientist untrained in electronics. :oops:

Also, any advice regarding how I can connect the data logger to the detector would be helpful (just let me know any further information you need).

Thanks!

Wil

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markspencer
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Joined: Wed May 07, 2003 9:45 am

Post by markspencer »

Hi,

Thank you for your question.

The ADC-10 would be suitable for data collkection at a rate of 1 per second. However, there are other factors that need to be taken into account.

1. How many channels do you need. If one channel is fine then again the ADC-10 would be suitable, otherwise an alternative would be required. Such as the ADC-2xx range or ADC-11.

2. The voltage range that your sensor is giving out has to be considered. Is it single ended or differential. The pico products only measure single ended. ie voltage with reference to ground. If you do not know what type the output is, ask the company you purchased it from. You also need to consider the voltage levels, does the sensor give out bipolar (negative and positive voltages), if so then the ADC-10 is not acceptable it only measures between 0 -5 volts, however, the ADC-42 or ADC-2xx range would be suitable.

3. The resolution required, if your sensor is sensitive on the voltage output ie very small changes. You will need a unit that can measure these changes. To calculate the sensitivity of a sunit divide the voltage range by 2^resolution.

ie ADC-10 has a 0 - 5 volt range, 8 bits and therefore the voltage differences it can measure is 19mV.

ie ADC-42 has a -5 to +5 volt range (10 volts total), 12 bits and therefore the voltage differences it can measure is 2.44mV.

The ADC-2xx has many different voltage ranges and thus is flexable in its sensitivity.

I hope this helps you in your selection, please do not hesitate to contact us again.

Best regards,
Regards,

Mark Spencer

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