Physics307L F08:People/Gleicher/Notebook/070910

--Erron C. Gleicher 17:57, 10 September 2007 (EDT)

For the first part of the lab, the instructions stated to connect the high voltage supply to the CRT via the connections G7 and C5. According to the lab manual a multimeter must be placed in series with the CRT to monitor the current in the circuit and keep it below 0.25mA.

Dr Koch and I assumed that the cathode of the CRT should be connected to the positive side of the supply, and C5 should be connected to the negative side of the supply (manufacturer schematic was . With Devon, the three of us tried connecting the multimeter in series according to the diagram of the lab manual, but we could not measure any significant current even with the high voltage supply at max output.

When the voltage is applied to the CRT, the heater functions but the "gun" only fires when the high voltage is quickly increased and then the output goes back to zero.

The magnet at the base of the tube was adjusted with no change in the operation. I then replaced the cables from the high voltage supply to the CRT with no change in the operation.