Olihou

At last I have been able to find locally a supply of UV sensor diodes OS100 from Orion Semiconductor: http://www.orion-semi.com/orionsemi.html I have tried it out, giving a few mV output when shined with a small UV lamp used for checking bank notes. Will look for suitable circuits to make a handy UVB Meter. Again any advice please with regard to the circuits, the curent amplifiers....and how to calibrate it evetually ....... ?????

Thanks OnOff. 6490 is probably OK for my application, except I am not sure how its unit :Index has been defined. I would prefer the unit uW/cm2. Besides, being a module with the amplifier the price will probably be high. I would prefer having a sensor diode and build the circuit my self. It saves money and it is fun in building something to one's own desire. Any one with other recommendations please ? :D

I have the interest to build a UVB meter for measuring the ultraviolet radiation intensity in the wavelength range from 280 to 320 nanometer. It will be used in my reptile house. The reptiles need UVB light for making vitamin D for bone health, but over doze will hurt them. UV meters are available as laboratory instruments and are quite expensive (hundreds of dollars). I think I can meet my target with a simple circuit. What I need is a UVB detector diode plus a high gain current amplifier. May be a budget of $50 will suffice? Any advice please, on the detector diodes and circuits? :D

Hello Jedi As an amateur I have the interesrt in building an ECG machine, and have now completed the basic amplifier circuit to acquire the ECG signal from my own body. Please see my previous posting in this forum: http://www.electronics-lab.com/forum/index.php?topic=1746.0 What I like to do may be some what similar to what you are planing to do, i.e. to display the signal on the PC, for ease of data manupulation and storage, etc. I am a hardware man and I find it difficult to get the part of job in computer programming. I have used a program downloaded from the Internet to display the ECG signal fed to the PC via the sound card. However since a sound card is basically an AC amplifier, the DC content of the ECG signal is lost and so there is some sort of distortion introduced. I am still figuring out how this problem can be solved by software means. May be we can share our experience with each other. I am not familiar with medical equipment in practical use -- would it be easy nowadays to have readily available digital output from the ECG machines ? So why do you need the ADC input board for this purpose? Best regards, Olihou

I see. Thanks a lot Audioguru !

Hi Audioguru and every body I am curious at the thinking that kit-makers put errors in their products purposely -- and if the kits would not work -- would that defeat their intention to sell the kits -- so they have protected their intellectual properties -- but not their businesses ? I have experience in using kits only a few times and am lucky that I succeed every time. It is nice to have some one in this forum poiting out the traps, saving the headache of many .....

Thanks Ante. I will try what you have recommended. I am now exploring Labview. I have already downloaded the program but it seems quite sophisticated that I need to spent some time to find out how it can be used. Oli

Hello Lou How about this? See if it helps. http://www.national.com/an/AN/AN-30.pdf The log amplifier output gives a DB equivalent of the input voltage. An ADC would be required should you need the digital form. Oli

YES ??????

Any one any advice please ? Just tell me if you are aware of any programme for Windows to convert a PC to a chart recorder -- Yes or no please? Oli

Is the output you have in mind digital or analog? If just for analog, there are functional circuits using op amps and diodes, as far as I can recall. Have you search for it in the cyber?

Your requirement is not very clear to most readers, I am afraid. Perhaps you can describe what your physics experiment is so that others will know what you really want. Also a block diagram of the circuit you like to have should help. Oli

I have some experience in powering low power circuits directly from 220V mains, without the use of a power transformer. Voltage regulation could be achieved by the use of zener diodes Darrins needs to tell others what kind of device/circuit he/she intends to power before others can offer advice. It could be rather dangerous unless every thing is well insulated, by one with good experience in high voltage circuits. Oli

Hi Does any one konw if there is any programme (preferrably free) for Windows to convert a PC to a chart recorder, using the audio card as the signal input? I have tried some programs for PC oscilloscope. However their time base is not long enough for recording signals for long time, say hours. I intend to have it for monitoring things like temparature variations. It will also be used for ECG. Thanks. Oli

Hello dicky Dimming by a trim-pot? What do you mean? What do you want to do? Oli?