Signal Converters are electronic devices that basically convert one type of radio signal frequency into another type. The signal converters are used for converting alternating current (ac) or direct current (dc) to another electrical waveform. When the signal converter is used to transform ac power into dc power, it is called rectifier and when it is used to convert dc power to ac power, it is termed as inverter. Some of the converters perform both these functions whereas others perform only one of these two functions. Signal converters can be differentiated broadly into two on the basis of conversion as:

Frequency Converter Voltage Converter

Analog to Digital converter Digital to Analog converter

Thyristors can be described as semiconductor devices having four layers and containing P and N type materials (PNPN) and they often act as switches, rectifiers and voltage regulators. Thyristors are commonly used in places, which involve high currents and voltages to control alternating currents. Thyristors are used in various devices like in motor speed controls, light dimmers, pressure control systems and liquid level regulators. The different types of thyristors based on their technologies are fast switching thyristors, field controlled thyristors, GTO thyristors, DIACs, MOS controlled thyristors, phase control thyristors, conducting thyristors, power thyristors, MA-GTO, LASCR, static induction thyristors and TRIAC's.

A transducer can be defined in simplest terms as a device that takes energy from one system and supplies it to another system in a different form. A transducer can be electrical, electronic, electro-mechanical, electromagnetic, photonic and photovoltaic. An example of transducer is an audio speaker that converts electrical voltage in the form of music or speech to mechanical cone vibration. The transducers can be differentiated on the basis of application and type. The various types of transducers on the basis of application are: Displacement Transducers

Flow Transducers Force Transducers Load Transducers

Pressure Transducers Temperature Transducer

A transformer is an electrical device that aids in increasing or reducing the voltage of an alternating current, which constantly keeps reversing its direction. Transformers are devices that give a simple and cheap option to change voltage and provide proper voltage for home appliances, lights, industrial machinery and other electronic components. Transformers can be broadly classified into five as:

Electronic Transformers Transformers by Function Miniature Transformers

Switching Power Transformers Transformers by Construction

A transistor is a semiconductor device that is used for a variety of purposes like for amplification, switching, voltage stabilization, signal modulation and a number of other functions. Transistors form the most important part of microprocessor and other circuits that govern the functioning of cellular phones and other modern electronic devices. Transistors are of many types depending upon the various types of technology like

IGBT	Power Transistors

Vacuum Tubes are electronic devices that are used for amplification, switching, modifying or creating an electrical signal by controlling the flow of electrons in an enclosed space filled with low-pressure gas. The tubes are generally made of glass but sometimes ceramic and metal is also used. Vacuum Tubes are now generally used in very high power consuming devices like microwave ovens, radio frequency heating in industries, power amplification in broadcasting, audiophile and professional audio devices. The famous vacuum tubes manufacturing companies are Shuuang (China), Reflector Corporation and Svetlana Electron Devices (Russia), Westrex Incorporated (USA) and JJ Electronic (Slovakia). There are many types of vacuum tubes and they are commonly differentiated according the technology used in them as: Diode vacuum tube, Pentode vacuum tube, Cathode Ray tube, Tetrode vacuum tubes, Travelling Wave tubes, Triode vacuum tubes, Klystron tubes.