E-1204B Electronic Medical Equipment

Energy Gap In GE Crystal 4 Probe Method:
The Four Probe Method is one of the standard and most widely used methods for the measurement of resistivity of semi-conductors. The error due to contact resistance, which is specially serious in the electrical measurement on semi-conductors, is avoided by the use of two extra contacts (probes) between the current contacts. As long as the resistance of the crystal and contact resistances are small compared with the effective resistance of the voltage measuring device (potentiometer, electrometer or electronic voltmeter), the measured value will remain unaffected. Because of pressure contacts, the arrangement is also specially useful for quick measurement on different crustals or sampling different parts of the crystal.

Probe Arrangement: It has four individually spring loaded probes,
Sample: Germanium crystal in the form of a chip.
Oven: It is a small oven for the variation of temperature.
Four Probe Set-up: Set-up consists of three units.
Multirange Digital Voltmeter:
Specifications:
Range: X1 (0 - 200.0 mV) & X10 (0 - 2.000 V)
Resolution: 100 uV at X 1 range
Accuracy: + 0.1 % of reading + 1 Digit
Impedance: 1 M
Display: 3-1/2 digit, 7 segment LED (12.5 mm height) with auto polarity and decimal indication.
Overload Indicator: Sign of 1 on the left and blanking of other digits.

Constant Current Generator.
Specifications:
Open Circuit Voltage: 18 V
Current Range: 0 - 20 mA
Resolution: 10 uA
Accuracy: + 0.25% of the reading + 1 Digit
Load Regulation: 0.03% for 0 to full load
Line Regulation: 0.05% for 10% changes
Oven Power Supply:

Glowing Led Indicates, when the oven power supply is 'ON'.

Complete with Manual and Connection Wire.