PASCO EM-8622 BASIC ELECTRICITY - Manual (Page 29)

25
012-04367E Basic Electricity
“Switch”
Diode
Resistor
A B C
Figure 9.1b
Figure 9.1a
Experiment 9: Diodes
EQUIPMENT NEEDED:
-Circuits Experiment Board -Digital Multimeter (DMM)
-Wire Leads -Two D-cell Batteries
-1000-
Ω
Resistor -1N4007 Diode
-330-
Ω
Resistor.
Purpose
The purpose of this lab will be to experimentally determine some of the operating characteristics
of semiconductor diodes.
Procedure
➀
Connect the circuit shown in Figure 9.1a using the 1N4007 diode you’ve been supplied and the
1000-
Ω
resistor. Use Figure 9.1b as a reference along with Figure 9.1a as you record your data.
Note the direction that the diode is
oriented, with the dark band closer to
point B.
➁ With the “switch” closed and the current
flowing, adjust the potentiometer until
there is a voltage of 0.05 volt between
points B and C (V
BC
). Measure the
voltage across the diode (V
AB
). Record
your values in the left-hand side of Table
9.1under “Forward Bias”.
➂ Adjust the potentiometer to attain the
following values for V
BC
: 0.1, 0.2,
0.3,.....2.0 volts. Record the two volt-
ages for each case.
➃ Remove the 1000-
Ω
resistor and replace it with a 330-
Ω
resistor. Repeat steps 3 & 4, going from a voltage of 0.3,
0.4,.....2.0 volts. Record the two voltages in each case.
➄
Reverse the orientation of the diode. Set the diode voltage
(V
AB
) to the values 0.5, 1.0,....3.0 volts. Measure the
resistor voltage (V
BC
) in each case. Record these values in
the columns labeled “Reverse Bias”.
Analysis
➀ Determine the current flow (I) in each setting by dividing
the voltage across the resistor (V
BC
) by the resistance.
Where you switched resistors, be sure to change the divisor.
➁
Construct a graph of Current (vertical axis) vs the Voltage across the diode, with the graph
extending into the 2nd quadrant to encompass the negative voltages on the diode.
A B
C
1N4007
R