Connect cables and cords
DANGER: High voltage is applied to the e/m
tube. Avoid contact with any part of the body.
• Only use shrouded patch cords for
connections.
• Make sure that the power supplies are OFF
before making the connections.
• Make sure that the power supplies are OFF
before installing or replacing the e/m tube.
IMPORTANT: Make sure that the AC voltage
switches on the power supplies are set for your
AC voltage level.
NOTE: Before connecting any cords or cables,
be sure that all power switches on the Power
Supplies are in the OFF position and all voltage
controls are turned fully counterclockwise.
Connect the cables and cords as described in the steps below to
finish setting up the e/m apparatus. The steps are labeled in the
diagram in Figure 2.
On the Tunable DC (Constant Voltage) Power Supply II,
connect the positive terminal of the 200 V DC output to the
Accelerating Voltage positive terminal on the platform.
Connect the negative terminal of the 200 V DC output to
the Accelerating Voltage negative terminal.
On the Tunable DC (Constant Current) Power Supply,
connect both terminals of the AC 6.3 V output to the
Filament terminals on the platform.
On the Tunable DC (Constant Current) Power Supply,
connect the positive terminal of the 3.5 A output to the red
terminal on the front Helmholtz coil.
Connect the black terminal of the front Helmholtz coil
to the black terminal of the rear Helmholtz coil.
Connect the red terminal of the rear Helmholtz coil to
the negative terminal of the 3.5 A output on the Tunable DC
(Constant Current) Power Supply.
(Not pictured) Connect the power cords to the power
supplies, then use these cords to connect the power
supplies to an electrical outlet.
Figure 2. The e/m apparatus with all cables and cords connected.
Experiment procedure
Adjust voltages and currents
Before beginning the experiment, be sure that all power switches
on the Power Supplies are in the OFF position and all voltage
controls are turned fully counterclockwise.
1. On the Tunable DC (Constant Voltage) Power Supply II, set
the Voltage Range Switch to 0 - 200 V.
2. For both power supplies, push in the Power Switch to the
ON position.
3. Allow the filament to heat up for about 5 minutes.
4. On the Tunable DC (Constant Voltage) Power Supply II, set
the Accelerating Voltage to 190 V DC.
5. Connect a wire between the Accelerating Voltage positive
terminal and the Deflection Plates Upper terminal to make
the electron beam appear.
6. On the Tunable DC (Constant Current) Power Supply,
increase the current to the Helmholtz coils. Watch the
electron beam and check to make sure that the beam
curves upward. Continue increasing the current until the
electron beam forms a closed circle.
- If the electron beam does not deflect, reverse the
polarity of one of the Helmholtz coils so that the
Product Guide | 012-14265D
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