1. Transient Signals of pn Junction Diodes

2. Transient Signals of pn Junction Diodes
Transient signals caused by buildup of minority carrier charge
Must build up charge to turn on pn diode
Must remove charge to turn off diode
Can test transient response by using resistor in series with pn diode
Circuit diagram for pn diode time delay measurement.

3. Transient Signals of pn Junction Diodes
Turn on transient: Must build up charge more quickly during transient to turn on diode before voltage relaxes to steady state. 3

4. Transient Signals of pn Junction Diodes
Turn off transient: Must drop voltage across resistor to discharge current from pn diode. 4

5. Transient Signals of pn Junction Diodes
Perform all measurements directly on the oscilloscope
Set function generator to 50 ohm output impedance
Attach black coaxial cable to the function generator
Attach gray coaxial cables to Channel 1 and Channel 2 of the oscilloscope
Use cursors to generate all voltage and time measurements

6. Transient Signals of pn Junction Diodes
Use Quick Print on oscilloscope to generate waveform output
Plug USB flash drive into oscilloscope USB port
Hit Quick Print on oscilloscope to save waveforms on flash drive
Use this data later in the lab report to demonstrate how you calculated the voltage and time parameters for these waveforms
We will not use scopegrab.vi to analyze data for this lab

7. Introduction to Lab Equipment
Agilent 6000 Series Oscillocope

8. Transient Signals of pn Junction Diodes
Turn on measurements:
IF = (VCh2,ss – VCh1,ss)/R
Vpk - Vss
tfr
Turn off measurements:
Vss – Voff
trd
Measured data for the turn on and turn off transients for square wave at 20 kHz
Plot waveforms at a particular voltage to demonstrate how you calculated IF and the relevant voltage and time parameters for the turn on and turn off transients 8

9. Transient Signals of pn Junction Diodes
Turn on and turn off transients generated from a 2.5 V to 0 V voltage transition on Channel 1 and Channel 2 (left) and measurements used to generate IF (right). 9

10. Transient Signals of pn Junction Diodes
Voltage and time measurements taken for turn on (top) and turn off (bottom) voltage transients generated between 2.5V to 0 V. 10

11. Transient Signals of pn Junction Diodes
Positive to negative transient: First reverse biases resistor to rapidly discharge current from pn diode during tsd before diode begins to approach reverse saturation current causing a rapid drop in voltage towards end of trr. 11

12. Transient Signals of pn Junction Diodes
Measurements: VF
IF = VCh1/R VR
IR = VCh1/R
tsd
trr
Measured data for positive to negative transient for square wave at 20 kHz
Plot the waveform at a particular voltage to demonstrate how you calculated the relevant voltage and time parameters for the reverse recovery transients 12

13. Transient Signals of pn Junction Diodes
Voltage (top) and time (bottom) measurements taken for the reverse recovery transient generated from a 0.9 V to -0.5 V transition. 13