1. Probes Arrangement
   • It has four individually spring loaded probes. The probes are collinear and equally spaced. The probes are mounted in a teflon bush, which ensure a good electrical insulation between the probes. A teflon spacer near the tips is also provided to keep the probes at equal distance. The whole - arrangement is mounted on a suitable stand and leads are provided for the voltage measurement. 
2. Sample
   •  Germanium crystal in the form of a chip (10X9X0.5mm)
3. Oven
   • It is a small oven for the variation of temperature of the crystal from the room temperature to about 200°C (max.) 
4. Four Probe Set-up, 55531
   • The set-up consists of three units in the same cabinet.

In this unit, intersil 3½ digit single chip A/D Converter ICL 7107 has been used. It has high accuracy like auto zero to less than 10μV, zero drift of less than 1μV/ °C, input bias current of 10pA max. and roll-over error of less than one count. Since the use of internal reference causes the degradation in performance due to internal heating, an external reference has been used.

1. Range : X1 (0-200mV) & X10 (0-2V)
2. Impedance : MW
3. Resolution : 100μV at X1 range
4. Display : 3½ digit, 7 segment LED (12.5mm height) with polarity and decimal indication
5. Accuracy : ±0.1% of reading ±1 digit
6. Overload Indicator : Sign of 1 on the left & blanking of other digits

1. Open Circuit Voltage : 18V
2. Current range : 0-20mA
3. Resolution : 10μA
4. Accuracy : ±0.25% of the reading ±1 digit
5. Load regulation : 0.03% for 0 to full load
6. Line Regulation : 0.05% for 10% changes