Ses Instruments Pvt. Ltd.

Adarsh Nagar, Roorkee, Uttarakhand

We offer Dependence of Hall Coefficient on Temperature usefull in physics and material science lab. The Hall voltage for p-carriers has opposite sign from that for n-carriers. Therefore if a semiconductor with p-type doping is gradually heated up, more and more electrons from its valence band will go to conduction band. As a result hall voltage would fall rapidly with temperature and even become zero or change sign. At the point of zero Hall Coefficient, it is possible to determine the ratio of mobilities b=e/h. The Hall coefficient inversion is a characteristic of only p-type semiconductors. The set-up consists of the following: 1. Hall Probe (Ge: p-type), HPP-22 Ge single crystal with four spring type pressure contacts is mounted on a glass-epoxy strip. Leads are provided for connections with the current source and Hall voltage measuring devices. Oven It is a small oven which could be easily mounted over the crystal or removed if required. Temperature Sensor Cromel-Alumel thermocouple with its junction at a distance of 1mm from the crystal. 2. Hall Effect Set-up :DHE-22 The set-up, DHE-22 consists of two sub set-ups, each consisting of further two units. Measurement of Probe Current & Hall Voltage This unit consists of digital millivoltmeter and constant current power supply. The Hall voltage and probe current can be read on the same digital panel meter through a selector switch. (a) Digital Millivoltmeter Specifications Range: 0-200mV (100V min.) Accuracy: 0.1% of reading 1 digit Impedance: 1M (b) Constant Current Power Supply Specifications Current: 0-20mA (10A min) Accuracy: 0.2% of the reading or 1 digit Load regulated: 0.05% for 0 to full load Line regulation: 0.05% for 10% variation Measurement of Thermo emf and Heater current The unit consists of a digital millivoltmeter and constant current power supply. The thermo emf of thermocouple and heater current can be read on the same DPM through a selector switch. (a) Digital Millivoltmeter Specifications : Range: 0-20mV Resolution: 10V equivalent to 0.25C in terms of thermo emf Accuracy: 0.1% of reading 1 digit (b) Constant Current Power Supply Specifications Current: 0-1A Accuracy: 0.2% of the reading 1 digit Line regulation: 0.1% for 10% variation Load regulated: 0.1% for 0 to full load 5. Electromagnet, EMU-50V 6. Constant Current Power Supply, DPS-50 7. Digital Gaussmeter, DGM-202/ DGM-102 The experiment is complete in all respect.

We offer PID Controlled Oven, this is high quality temperature controlled oven suitable for Four Probe Set-up, testing of electronic components & study of temperature transducers etc. The oven has been designed for fast heating and cooling rates which enhances the effectiveness of the controller. While the basic design of the controller is around the PID configuration for its obvious advantages, wastage of power is avoided by using a Pulse Width Modulated (PWM) switch. This combination has the advantages of both on-off controller and linear PID controller. The result is a good stable and accurate temperature control. A platinum RTD has been used for sensing the temperature. A Wheatstone bridge and an instrumentation amplifier are used for signal conditioning. Feedback circuit ensures offset and linearity trimming to a great degree of accuracy. The set and measured temperature are displayed on 3? digit DPM through selector switch. Specifications of the Oven :Temperature Range: Ambient to 200C .Resolution: 0.1C.Short Range Stability: 0.2C.Long Range Stability: 0.5C.Measurement Accuracy: 0.5C (typical).Oven: Heating Chamber Inner Diameter: 25mm, Height: 100mm (Specially designed for Four Probe Set-Up Component testing)Sensor: RTD (A class).Display: 3 digit, 7 segment LED (12.5 mm) with auto polarity and decimal indication.

We offer Study of Thermoluminescence of F-centers, TLX-02 in Alkali Halide Crystals. A colour centre is a lattice defect that absorbs visible light. These colour centers can be produced by heating the crystal in excess of alkali vapour or by irradiation. The colour centers formed due to trapped electrons or trapped holes can be destroyed (bleached) by illuminating with light or warming. Important information about the colour centers can be obtained from the plot of luminescence intensity vs. temperature, taken at a constant heating rate called glow curve. It may contain one or many glow peaks, depending upon whether there are one or several different kinds of traps. The experiment consists of the following: (a) Experimental set-up for creatingvThermoluminescence (1) Sample: KBr (TLS-KBr) and KCl (TLS-KCl) single crystal (2) Thermoluminescence Temperature Meter, TL-02 Digital Thermometer with RTD sensor Oven power supply (3) Sample holder (4) Thermoluminescence Oven (upto 423K), TLO-02 (5) Black Box, TL-BBx (b) For measurement of Luminescence Intensity (1) Photomultiplier tube 931A, TL-PMT (2) PMT Housing with biasing circuit and connecting coaxial cables, TL-PMH (3) High Voltage Power supply, EHT-11 (4) Digital Nanoammeter, DNM-121 Complete in all respect, only X-ray facilities are required to create F-centers in the crystal.