poor man's PMT

Yup. Using a nice swoopy Agilent 10 GHz scope for the back end, at least for now. I'm looking forward to playing with it. If it goes into production, they'll want a dedicated digitizer.

Cheers

Phil Hobbs

Make that 5,134,276, sorry.

Cheers

Phil Hobbs

Grumble, Sorry (Just laziness on my part.) I tried eternal sept. for a wh ile, but google ?was? easier.

Yup I remember the transistor tester circuit.

Sure. I've done plenty, just none right now.

I'd like to be able to change the integrator time constant.

(The alternative is Labview, of

(I dislike labview too.. I'm semi-tasked with looking it Labjack as a poten tial data to computer interface. I'm not sure about the software part thou gh.

Sounds fun. Do you have a target price (or market)? (I assume you won't be aiming at the teaching market.)

Throwing some numbers down I figure we could do your simple circuit (two PD 's, three transistors, one opamp.) for maybe ~$150- $250. And sell it for ~$450-700. It'd probably only be 30 or 40dB worse than yours.. :^)

George H.

I'd use the MAT14 if I could possibly afford it--compared with other devices it's magic at low speed, and you can do the on-chip ovenizing trick to stabilize the log output. (See my 1997 Applied Optics paper,

Mine would be a major upgrade over the New Focus Nirvana, which is limited to two inputs, 125 kHz, and 50 dB, so that gives an idea of what the price point might be.

The loop bandwidth will be user-settable, and there will be a spectroscopy mode, where it's log-only and very much faster, i.e. > 1 MHz loop bandwidth, at least at higher photocurrent. A fair amount of that stuff is TBD still.

Cheers

Phil Hobbs