Study of P-N Junctions

Advanced Level Apparatus

Measure semi-conductor properties for many standard junction devices at various temperatures. This advanced level apparatus measures the characteristic properties of commercially available germanium or silicon diodes, various LEDs types, and base-emitter/collector-base junctions of a transistor. Through these measurements students gain knowledge of the material’s characteristics and an insight into the properties of the materials used in the fabrication of the junction. All the necessary instrumentation is integrated so that a minimum of external connections is required. Setup includes everything required except for a cathode ray oscilloscope, which you provide. 110/220 V, 50 Hz/60 Hz.

Experiments may be performed to determine:
1. Reverse saturation current I0 and material constant
2. Energy band-gap and temperature coefficient of the junction voltage
3. Junction capacitance

The experimental set-up includes:
1. Study of P-N Junction Model, PN-1
a. 3½ digit Digital Power Meter for current/temperaturemeasurements
b. 3½ digit Digital Power Meter for bias voltage/junction voltage measurements.
c. Two parts to connect the diode: one for experiments 1 & 2; one for experiment 3.
d. Two fixed frequency oscillators (5 KHz & 20 KHz) with the 200 mV output

2. Fast temperature controlled oven with sensor

3. Set of samples
a. Transistor BC109 (base-emitter)-Si
b. Transistor AC126 (base-emitter)-Ge
c. Diode 1N 5408/1N 4002-Si