Electrical Engineering

 A bipolar junction transistor consists of three regions of doped semiconductors. A small current in the center or base region can be used to control a larger current flowing between the end regions (emitter and collector). The device can be characterized as a current amplifier, having many applications for amplification and switching  A transistor in a circuit will be in one of three conditions Cut off (no collector current), useful for switch operation. In the active region (some collector current, more than a few tenths of a volt above the emitter), useful for amplifier applications In saturation (collector a few tenths of a volt above emitter), large current useful for "switch on" applications. 

  General Purpose OPAMP Moderate values of the key parameters • Current differencing OPAMP ( have different internal structure) • Non-inverting input is derived from inverting input • Current mirror circuit is used

What is white noise? In communication systems, the noise is an error or undesired random disturbance of a useful information signal, introduced before or after the detector and decoder. The noise is a summation of unwanted or disturbing energy from natural and sometimes man-made sources. Noise is, however, typically distinguished from interference, (e.g. cross-talk, deliberate jamming or other unwanted electromagnetic interference from specific transmitters), for example in the signal-to-noise ratio (SNR), signal-to-interference ratio (SIR) and signal-to-noise plus interference ratio (SNIR) measures. Noise is also typically distinguished from distortion, which is an unwanted alteration of the signal waveform, for example in the signal-to-noise and distortion ratio (SINAD). In a carrier-modulated passband analog communication system, a certain carrier-to-noise ratio (CNR) at the radio receiver input would result in a certain signal-to-noise ratio in the detected message signal

What is Solid? The sate of matter in which materials are not fluid but retain their boundaries without support and having three dimension (length, breadth and thickness) as a geometric body or figure. Example: » Atomic solid, » Metallic solid, » Molecular solid and  » Ionic solid   Solid can be divided in Crystalline and non- Crystalline of Solid

 A transducer is defined as a device that receives energy from one system and transmits it to another, often in a different form (electrical,mechanical or acoustical). d e e o (e ec ca , ec a ca o acous ca ) „ Basically, there are two types of transducers : 1) Electrical 2) Mechanical „ The electrical output of a transducer depends on the basic principle involved in the design. „ The output may be analog, digital, or frequency modulated

The losses in a dynamo:  When the energy is delivered ta a dynamo ,then not all the energy is available from that dynamo.There are some losses such as- Copper loses Cores losses Mechanical losses 

A Dynamo is a machine for converting rotary motion into electricity. The usual form of dynamo consists of a circular metal frame which is magnetized so as to create a strong magnetic field across the internal space.