Hello Anthony!
Experiments...well, honestly, I'm not sure I have an objective here!
Also, I have the old "Laser Listener" article from a very old "Radio Electronics" magazine. It used a laser reflected off a window to a rifle scope-aided phototransistor to pick up room sounds. I always...
Tonight I had a chance to run it for a while. I ran it for 16 minutes. The temperature of the single ballast resistor topped out at 303F !
It wasn't building much temperature, so I think that was steady state.
Measurements were taken with an Extech IR thermometer at a distance of about...
Ok - I've made some progress! I ended up buying a high voltage probe for my multimeter. I installed a 120K / 3W ballast resistor right before the anode, then the tube, then back to the Melles Griot power supply.
I put the multimeter ground clip on the tube's cathode connection (which is...
Ok - that was quick. I wired in the 1k resistor on the cathode and measured a voltage drop of 6.45 V. Therefore, on a 1k resistor, that's 6.45 mA of current.
6.45 mA is the rating of the power supply, so I suppose it may have been maxed out?
This was with 200K ballast resistor on the...
Thanks Tony! Great suggestion - I should have thought of that !
I suppose that once I learn the current with a given ballast, I can make sure that ballast resistor is rated to dissipate that amount of current. (P = I^2 * R).
I guess what I was wondering was, couldn't I just increase the...
I need some help on my ballast resistor.
I bought a "1 mW" HeNe laser at the Dayton Hamvention electronics flea market around 1990 ! It had a tube and a power supply "kit" which consisted of a printed circuit board and components that you put together. Everything was fine, and, I was able...