Ignition systems

Two important types of ignition system are contact breaker point ignition system and electronic ignition system. The difference lies in the primary circuit. In contact breaker point ignition system, for opening and closing the primary circuit, contact breaker points are used. An electronic ignition system uses electronic control unit for this operation. Secondary circuit remains almost same in both the cases. Very high voltage is developed in secondary circuits. A typical value is 47 kV. In order to handle this high voltage, the ignition coil, the distributor and wiring are altered in the secondary circuit. To deal with high voltages, spark plugs are used in electronic ignition systems. Air-fuel mixtures are used for better fuel economy and lower emission. In an electronic ignition system, a timer sends electrical pulses to an electronic control unit which switches off the flow of current to the primary winding. Either a pulse generator or a Hall effect sensor can be used as a timer. The high voltage induced in the secondary winding is distributed to spark plugs.

Compressed natural gas (CNG)

Natural gasoline can be obtained by mixing petroleum with natural gas. Natural gasoline is a highly volatile liquid, and on cooling, it condenses to form condensed natural gas (CNG). Nowadays CNG is widely used as fuel in many automobile vehicles. The fuel feed system is similar to a LPG fuel feed system. Petrol-driven cars can be easily converted into CNG-driven mode by using some CNG auto conversion kits. Some of the early CNG vehicles are Hindustan Motors make Ambassador Car, Ashok Leyland’s Bus, Tata make Indica Car and Fiat’s Uno Car. Some of the advantages of CNG driven vehicles are less toxic gas emission, minimum air pollution, minimum noise and negligible fuel evaporative losses. 

Musical Instrument Digital Interface (MIDI)

Infrasonic, audiosonic, ultrasonic and hypersonic are different frequancr ranged sound waves or acoustic waves. Another property of sound is amplitude. An audio signal is converted into digital format by using an analog-to-digital converter in computers. Sampling rate is the rate at which a continuous waveform is sampled. Musical Instrument Digital Interface is a technique developed to exchange musical information to computers. MIDI protocol is a binary form music description language. A binary code here represents a musical action. There are two components in MIDI interface. First one is a hardware which specifies the physical connection of musical instruments. Second one is a data format which facilitates information encoding. This digital data format is in grouped MIDI messages format. On playing a key in a musical instrument, the MIDI interface generates a MIDI message. This message defines the start of each score and its intensity. The two timing codes used here are MIDI timing code and SMPTE timing code.

DNA chips

DNA chips helps to obtain information about an individual’s genetic characteristics. The basic principle involved in DNA chips is that complementary DNA strands stick together. By a suitable denaturization technique, single stranded DNA segments of known sequence are prepared initially. These DNA strands are then mounted on microarray plates. The unknown sample is then placed on this array. On finding its complement, unknown sample sticks to it. Some quality fluorescent markers can be used for fine binding of hybridized strands. DNA chip technology can be used for the identification of an individual’s SNPs which is related to a specific disease. Medical field makes use of this technology for diagnosis, prevention and treatment. This technology is successfully tested in determining whether a woman possesses mutations of the BRCA1 gene.  Expression profiling and analysis is a technique used in DNA chips related technology where classification of types of cancers and other diseases are possible.