Basic Electronics/Electrical Projects & Kits

Get our latest collection of basic electronics projects here -- all tested and reviewed for use in mini projects and main projects or even just as hobbyist projects!
Smart Emergency Light Save Rs. 75.00
Rs. 300.00
Rs. 225.00

Smart Emergency Light

Smart Emergency Light

by KNS Pvt Ltd
Save Rs. 75.00
Rs. 300.00
Rs. 225.00

Summary

Now you need not fear dark nights when power breaks down. Here’s a white LEDbased Emergency light that automatically turns on when the mains power supply fails.

Learning

Things which you can learn:

*Application of NE555 inastable mode.
*Application of LDR in light and dark.
*Application of bridge rectifier.

Product Description

Build an Emergency light which will automatically switch on when the power fails, thus obviating the need to search the light and switch it on manually!!

Working


The switching circuit is built around an NE555 timer (IC1), which is wired in monostable mode. When a low voltage is applied at trigger pin 2 of IC1, the timer activates and its output pin 3 goes high. It remains in that state until IC1 is triggered again at its pin 2. Light-dependant resistor LDR1 is connected between the positive supply of the battery and trigger pin 2 of IC1. Resistor R3 is connected between pin 2 of IC1 and ground. The resistance value of LDR1 remains high in the dark (at night) and low in ambient light (in daytime). This phenomenon is utilised to control the switching circuit.

The working of the circuit is simple. In daytime, when ambient light falls on LDR1, its resistance decreases to make trigger pin 2 of IC1 high. As a result, output pin 3 goes low and the LEDs(LED1 through LED7) remain off. At night (in the dark), the resistance of LDR1 increases and a low voltage is applied to trigger pin 2 of IC1. This activates the monostable and its output goes high to make all the LEDs glow.

 

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Versatile Power Supply

Versatile Power Supply

by KNS Pvt Ltd
Rs. 425.00

Summary

The Versatile Power Supply is a DC regulated variable power supply that is capable of delivering DC voltages ranging from 3.3 Volts to up to 15 Volts with 1Amp current output using a variable voltage regulator IC LM317. Build the kit and enjoy powering up your awesome project! No. of ICs used: 1

Learning

Things you can learn:

*Application of the voltage regulator IC LM317.
*Application of NPN transistors as switches.
*Basics of Voltage Step downing
*Concepts and implementation of bridge rectifiers

Product Description

A variable power supply is a must for those who are looking forward to taking their project building to the next level. Armed with this system you can have a clean DC supply without spikes.

Working:

In the Versatile Power Supply circuit, the AC mains is stepped down by a transformer (X1) to deliver the secondary output of 18V AC at a maximum current of 1A dependent upon the load. The transformer output is rectified by the bridge rectifier comprising of four diodes (D1 through D4), filtered by a capacitor (C1) and fed to the voltage regulator IC LM317 (denoted as IC1). IC1 is a 3-terminal positive regulator capable of providing 1.2V to 37 volts at 1.5A current to the load.


Resistor R13 and selected combinations of several other resistors (R1 through R12) are used to produce approximately 3.3V, 5V, 6V, 9V, 12V and 15V at the output. The desired resistors are selected by switching into conduction one of the six PNP transistorsBC558 (T1 through T6) by grounding the corresponding transistor base using a rotary switch (S1). For example, to get regulated 3.3V, simply rotate the knob of the rotary switch to the 3.3V position. Consequently, transistor T1 is forward biased to switch resistors R1 and R2 (in series) across Adj pin of LM317 and ground to produce 3.3V.


Other voltages can be produced in the same way by using rotary switch S1. Capacitor C2 bypasses any ripple in the output. Diode D5 is used as the protection diode. Use a heat-sink for dissipation of heat from IC LM317. The fuse-rated lamp provides protection against short circuit.

 

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