Category: Electronics Projects

There are various type of emergency light circuits. Every circuit has its own importance and utility. But size, cost and efficiency of the circuit are some of the main feature of interest. A very simple circuit of mini emergency light is given here. In normal daylight or electric light, the LDR offer very low resistance. So the positive voltage is applied to the base of transistor T1, making it reverse biased. Therefore, T1 does not conduct in presence of light. As transistor T2 also is reverse biased it does not…

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The fluorescent tube-light requires additional gear such as the copper ballast and starter for normal operation. These two are required to provide the initial high voltage for ionization and thereafter to limit the current through the tube to safe values. It has been observed that the illumination efficiency of the tube-light when excited by high frequency power source is higher than that when excited at the 50Hz line frequency. Moreover, the power factor and the efficiency of the bulky copper ballasts are poor. Hence, electronic ballasts circuit were developed to…

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The compression and expansion are two important techniques used by audio engineers during recording and reproduction of program material. The compression of dynamic range of program material (records, speech or musical broadcasting) permits maintaining constantly high modulating level while the expansion, when used with the reproduction of compressed material, restores the dynamic range and creates a ‘live’ music. Thus, we are created simple and basic project Expander Compressor Unit Circuit. Circuit Description of Expander Compressor Unit Circuit | Compander Creating these effects is costly and complex, and beyond the scope of amateur…

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The hearing aid circuit available in the market are fully transistorized and generally use a single pen cell. The hearing aid circuit uses an IC LM358 (IC1) for the same purpose which give better sensitive and performance. You can also check DIY Hearing Aid Circuit using 555. Circuit Description of Hearing Aid Circuit Operational amplifiers are used here in their simplest from non-inverting AC amplifier with a gain of 100. Op-amp A1 forms the first-stage amplifier. Second-stage amplification is given through op-amp A2. Hence the total gain is 10,000. Resistors…

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Here is a project for audio running lights circuit which uses filament bulbs instead of LEDs. The circuit employs seven channel darlington array IC ULN2004 and seven reversed biased zener diodes having different breakdown voltages. At low audio level, zener diodes having low breakdown voltages will conduct and corresponding lamps will light up. When output level increases, the other diodes will also conduct. As a result, you can see a very fine display of ‘moving’ light bulbs from top to bottom or from left to right, as per their arrangement.…

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