TECHNO BRACKET

21. Determine the conductivity of a semi-conductor 22. Determine the number of electrons in conduction band in terms of band gap E G and also find the number of holes in valence band. Write a procedure to find the number of electrons in the conduction band of a semiconductor. Derive an expression for the total number of holes in a semiconductor. What is intrinsic concentration of charge carriers in a semiconductor? Derive an expression for carrier concentration in terms of band gap (E G ). Write a short note on conductivity and mobility of semiconductor material. Derive a mathematical expression for electrical conductivity. What do you mean by relaxation time, collision time and mean free path. What is Fermi level? How does it depend on temperature? Derive an expression for Schrodinger wave equation. Derive the expression for conductivity of a semiconductor. What is basic crys

1. Differentiate between crystalline, amorphous and polycrystalline solids. 2. Define the following:   (i) Unit cell ( ii) Space lattice (iii) Lattice parameter and crystallographic planes (iv) Lattice parameter of unit cell (v) Crystal system  3.  Explain the seven crystal system  4. Differentiate between simple cubic, FCC and BCC. 5.Define atomic packing factor. Calculate its value for body centered cube. 6. Find the fraction of the FCC unit cell volume filled with hard spheres. 7. Find the packing fraction of simple cubic structure. 8. What is atomic radius? calculate it for SC, BCC and FCC. 9. Drive the formula for density and lattice constant.  10. What do you mean by Miller Indices? 11. What are important features of Miller Indices. 12. What do you understand by atomic bonding? Differentiate  between ionic and covalent bonds. 13. Write a short note on covalent bond and metallic bond. 14. What are the differences between crystalline and non-crystall

USBasp - USB programmer for Atmel AVR controllers USBasp is a USB in-circuit programmer for Atmel AVR controllers. It simply consists of an ATMega48 or an ATMega8 and a couple of passive components. The programmer uses a firmware-only USB driver, no special USB controller is needed. Features Works under multiple platforms. Linux, Mac OS X and Windows are tested. No special controllers or smd components are needed. Programming speed is up to 5kBytes/sec. SCK option to support targets with low clock speed (< 1,5MHz). Planned: serial interface to target (e.g. for debugging). Download Firmware and circuit          The following packages include circuit and firmware Drivers On Linux and MacOS X no kernel driver is needed. Windows requires a driver for USBasp: usbasp-windriver.2009-02-28.zip (70 kB) Note: Windows Vista/7 x64 requires drivers with digital signature. Currently there are no official drivers for libusb (USBasp software is based on i