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Hi everyone, I recently completed the construction of a spectrometer that studies electron transfer events in inorganic molecules. I am trying to further improve my design however, mainly one major flaw.
I'd like to control where the output of my photomultiplier (PMT) tube is going using a set of BJT transistors as we currently have to manually plug the BNC into the appropriate device. Given the complexity of the setup, it's not feasible to expect workers in the future to be able to do this.
I am somewhat unsure as to how BNC/coax cables operate and would like to ensure that my circuit will work before I invest the effort into building the switch box.
The TTL logic to each gate is to come from an NI USB 6008 IO box.
Best Answer
It will not work (reliably) like this.
The transistors turn on when their base voltage is below their emitter voltage. But here the emitters are DC coupled to the PMT output. So for this to work the PMT output needs to have a DC-component at the TTL high level.
I would consider: