Hi all,
I have a project that I would like your input on the general design concept and how to achieve the desired outcome. I'll try to explain the concept below.
We have a photomultiplier (PMT) that is connected to a typical fixed gain pico amplifier circuit using an AD549. The gain of the PMT, and hence its output, is controlled via a DC PMT control voltage. The "final" output will need to be connected to a 4.5 digit digital panel meter (DPM). Let's say 10V equals 100.00 on the meter.
In practice the PMT will be subjected to near zero light, this is when the zero button is pressed. Then the PMT will have a fixed amount of light, and this is when the full scale button is pressed. Now you can measure the amount of light hitting the PMT between 0 and 100.
I need a circuit that will do two things:-
1. A press of a zero button will make the DPM read zero volts (000.00). I imagine applying an offset to the output, or maybe to the input, of the pico amp in some way.
2. A press of a full scale button will change the DC PMT control voltage until the DPM reads 100.00.
Apart from the pico amp which is analog, how is the best way to do the above. Keep it all analog or or do we go digital with say a CPU.
Ideas and more questions would be greatly appreciated.
TIA
Greg
I have a project that I would like your input on the general design concept and how to achieve the desired outcome. I'll try to explain the concept below.
We have a photomultiplier (PMT) that is connected to a typical fixed gain pico amplifier circuit using an AD549. The gain of the PMT, and hence its output, is controlled via a DC PMT control voltage. The "final" output will need to be connected to a 4.5 digit digital panel meter (DPM). Let's say 10V equals 100.00 on the meter.
In practice the PMT will be subjected to near zero light, this is when the zero button is pressed. Then the PMT will have a fixed amount of light, and this is when the full scale button is pressed. Now you can measure the amount of light hitting the PMT between 0 and 100.
I need a circuit that will do two things:-
1. A press of a zero button will make the DPM read zero volts (000.00). I imagine applying an offset to the output, or maybe to the input, of the pico amp in some way.
2. A press of a full scale button will change the DC PMT control voltage until the DPM reads 100.00.
Apart from the pico amp which is analog, how is the best way to do the above. Keep it all analog or or do we go digital with say a CPU.
Ideas and more questions would be greatly appreciated.
TIA
Greg