Study of P-N Junctions

We offer Study of P-N Junction, this is an advanced level experiment to be performed on commercially available diodes viz. germanium or silicon diodes, various types of LED’s and also on the base-emitter/collector-base junctions of a transistor. The results of the experiments not only give the device characteristics but also provide an insight into the properties of the materials used in the fabrication of the junction. In the set-up, all the necessary instrumentation is integrated as a result of which a minimum of external connections need to be made by the user. A CRO is the only accessory that is required.

The following studies can be carried out.

(i)  Reverse saturation current l0 and material constant h
(ii) Temperature coefficient of junction voltage dV/dt
(iii) Energy band-gap VG0
(iv) Junction capacitance

The experimental set-up consists of the following:

(1) Study of P-N Junctions, Model PN-1
   
(a) 3½ digit DPM for current/ temperature measurement.
(b) 3½ digit DPM for bias voltage/ junction voltage measurements.
(c) To connect the diode – one for experiment 1 & 2 and other for experiment 3.
(d) Two fixed frequency oscillators (5KHz & 20KHz) with the same output (200mV).

(2) Fast temperature controlled oven with sensor, PNO-01

(3) PNJ-Sample
   
    (a) Transistor BC109 (base-emitter)-Si
    (b) Transistor AC128 (base-emitter)-Ge
    (c)  Diode: IN 5408/IN 4002-Si

The unit is supplied complete with a detailed instruction manual. Sufficient theoretical description is included for a proper understanding. This is followed by a step-by-step procedure and a typical set of readings and results.

The set-up is complete in all respect, except a CRO which is required for measurement of junction capacitance.

The experiment is complete in all respect.