Curve Tracing
Content
Semiconductor Curve Tracing with an Oscilloscope Press
+
SW1 Sweep
25V PS
Release
CH2
R1 100 R2 1K
R4 10K
100uA/V
R3 1K
1mA/V
C1 330
C2 0.22
CH1: CH2: Horiz: Display mode: Persistence:
UUT
Pos = +4 Div Pos = -3 Div 50mS X/Y Infininte
CH1
-
1N914 1N4000 1N2069 1N5401
1N5817
If = 5V/1K=5mA/Div
Sample sweeps, R3 (1K)
CH2=Y=-3Div CH1=X=+4Div
NTE110 No UUT
0 Vf = 100mV/Div
0
The RC formed by R1/C1 raises the voltage across R3/UUT slowly enough so that the oscilloscope can take samples at various I/V points. R2 discharges C1 when the button is released. Press the button multiple times to allow the scope to get enough samples to fill out the curves. Curves at various temperatures can be automatically overlaid by changing the temperature of the UUT and then re-sweeping. Curve tracers simply automate the button portion of the above circuit to continually retrace the curve or digitally sample and then display a single sweep (A single sweep is better as this prevents heating of the UUT!)
+
SW1 Sweep
25V PS
Release
CH2
R1 100 R2 1K
R4 10K
100uA/V
R3 1K
1mA/V
C1 330
C2 0.22
CH1: CH2: Horiz: Display mode: Persistence:
UUT
Pos = +4 Div Pos = -3 Div 50mS X/Y Infininte
CH1
-
1N914 1N4000 1N2069 1N5401
1N5817
If = 5V/1K=5mA/Div
Sample sweeps, R3 (1K)
CH2=Y=-3Div CH1=X=+4Div
NTE110 No UUT
0 Vf = 100mV/Div
0
The RC formed by R1/C1 raises the voltage across R3/UUT slowly enough so that the oscilloscope can take samples at various I/V points. R2 discharges C1 when the button is released. Press the button multiple times to allow the scope to get enough samples to fill out the curves. Curves at various temperatures can be automatically overlaid by changing the temperature of the UUT and then re-sweeping. Curve tracers simply automate the button portion of the above circuit to continually retrace the curve or digitally sample and then display a single sweep (A single sweep is better as this prevents heating of the UUT!)
