Four Probe Method for Resistivity Measurement
Item Code : SK012
Principle and Working:
The four probe method to find the resistivity of a germanium (Ge) crystal is given by:
where V is the voltage, I is the current (in mA), and s is the spacing between the two point electrodes.
The energy band gap is given by:
where T is the absolute temperature, k is the Boltzmann constant, and e is the charge of an electron.
In the current setup, four probes are placed collinearly with equal spacing on the sample. Current is applied through the two outer probes, and the voltage is measured between the two inner probes. This method eliminates errors due to contact resistance, as the current and voltage paths are separate.
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- Built-in Temperature sensor with seven segment digital display.
- Dual Purpose seven segment digital display.
- Multi-Turn Pot for fine tunning of Current.
- Pointed spring loaded probes ensure good electrical contacts with the sample.
- Different samples can be tested.
- Measurement of resistivity of semiconductor by four probe method.
- Determination of Energy Band Gap.
- Power supply : Voltage range X1 (0-200.0mV DC) & X10 (0-2.00 V DC), Current Range 0-20mA DC.
- Oven Supply : 60V AC, Heating resistance 35 ohm, Temp. range ambient to 200º C, Fuse 2A.
- Temp. sensor : PT-100, range -10 to 250º C.
- Four Probe : Spring loaded, spacing 2.5mm, connection via 4mm
- Arrangement : 4mm safety socket.
- Sample : p-type Ge Wafer, Size : 12 x14 x 0.5mm Resistivity 1~10 ohm-cm, Orientation <100>.
| S.No. | Item Name | SK012 |
|---|---|---|
| 1 | Power supply for four probe setup | 1 |
| 2 | Four probe Assembly | 1 |
| 3 | Oven | 1 |
| 4 | PT-100 Sensor (Built-in) | 1 |
| 5 | Screw driver (liner) | 1 |
| 6 | p-type Ge crystal | 1 |
| 7 | n-type Ge crystal (optional) | 1 |
| 8 | Power Cord (Main Lead) | 1 |
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