Posts tagged ‘931A’

Direct Measurement of the Speed of Light using a Cheap Laser Diode – II

In my previous blog post, I discussed the basic TOF method for direct measurement of the speed of the light. In order to measure the time of flight accurately, we need to be able to both generate and detect very fast rising signals. One way to generate a fast rising, short duration laser beam is via an avalanche pulse generator as we discussed previously. In this blog post, we will take a look at the receiver end and conduct some experiments. A video of the experiment is included towards the end. Continue reading ‘Direct Measurement of the Speed of Light using a Cheap Laser Diode – II’ »

Reverse Engineering a Beseler PM2L Color Analyzer

I recently acquired an old Beseler PM2L color analyzer. This kind of color analyzer was designed to analyze the color or exposure of film negatives at a certain location by comparing the intensity of the filtered light of each color channel (CMY and white). The PM2L model was made in the 70’s through early 80’s and has long become obsolete. But since it has a 931A photomultiplier tube (PMT) inside, you can easily repurpose it for other uses. And the good news is, these old color analyzers are cheap on eBay. You can usually grab one for a price cheaper than a bare PMT itself. Continue reading ‘Reverse Engineering a Beseler PM2L Color Analyzer’ »