Delayed ON LED

john April 17, 2009 2 Comments
Description. Here is very simple circuit in which the LED becomes ON only after a preset time the power supply is switched ON. When the power supply is switched on the transistor will be OFF. The capacitor now charges via the preset R3 and when the voltage across C1 is sufficient, the transistor switches ON and LED glows. The ON delay depends on the value of POT R3 .You can increase the time delay by increasing the resistance of...
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Battery operated mini night lamp

john February 28, 2010 13 Comments
Description. This is the circuit of a low power LED night lamp that will automatically switch OFF at day time. The CMOS timer IC TS555CN is wired as a square wave generator operating at around 5Hz.The output voltage from the IC1 is doubled using the combination of capacitor C2 and diode D2 in order to drive the LED. The LED can be a bright white LED. At day time the resistance of LDR drops to few K Ohms and...
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4W Fluorescent lamp driver.

john February 28, 2010 17 Comments
Description. This is a simple 4 W fluorescent lamp driver circuit that can be operated from a 12 V supply.The first part of the circuit includes a NE555 timer IC wired as an astable multivibrator.The output pulses from the IC are amplified by the transistor Q1.The transformer steps up the collector voltage to around 1KVto drive the fluorescent lamp. Before using the circuit, set the R2 at full resistance and switch on the supply, now adjust R2 so that...
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LED torch using MAX660

john April 7, 2010 20 Comments
Description. This is a simple LED torch circuit based on IC MAX660 from MAXIM semiconductors. The MAX 660 is a CMOS type monolithic type voltage converter IC. The IC can easily drive three extra bright white LEDs.The LEDs are connected in parallel to the output pin 8 of the IC. The circuit has good battery life. The switch S1 can be a push to ON switch. Circuit diagram with Parts list. Notes. Assemble the circuit on a general purpose...
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Mains operated LED lamp

john January 27, 2014 97 Comments
CircuitsToday has introduced an online bookstore where 4 books on basic electronics are reviewed in detail. These books are written by renowned authors like Forrest M Mims, and other famous personnels. Please go through the reviews and buy them from here:- 4 GREAT BOOKS TO LEARN BASIC ELECTRONICS Description. This is a very simple and cost effective mains operated LED lamp which gives a very bright white light.Since no transformer is used, the circuit is very compact and light weight.The...
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Two star flasher circuit.

john August 17, 2009 2 Comments
Description. A circuit that can be used to flash two Christmas stars alternatively is given here. The IC1 NE 555 is wired as an astable multivibrator here. When there is a positive pulse from the output of IC1, the transistor Q1 conducts and the relay K1 gets activated. The lamp L2 connected via the N/O contact of the relay glows. When the output pulse of the IC goes low, the Q1 goes OFF and the relay gets deactivated. Now...
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Flashing LED unit

john November 15, 2011 29 Comments
Description. The circuit given here is designed as an LED flasher which produces a rotating effect when the LEDs are arranged properly. The circuit has very low current consumption and can be operated from even 3V button cells. The IC 1 (CMOS NE555) is wired as an astable multivibrator wired at a duty cycle of 50% and 4Hz frequency and drives LEDs D1 to D6.The second IC, IC2 (CMOS NE555) is working as a trigger pulse inverter and drives...
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Mains operated LED night lamp

john February 17, 2009 53 Comments
Description. Here is a simple and powerful LED based night lamp circuit that can be operated directly from the 230V mains supply. The are total 24 white LEDs used and the lamp produces an output of around 15W.The resistance R1 and capacitor C1 provides necessary current limiting. The circuit is sufficiently immune against voltage spikes and surges. Circuit diagram with  Parts list. Notes. Assemble the circuit on a general purpose PCB. The capacitor C1 can be polyester type. White...
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Night security light

john July 9, 2014 19 Comments
Description.  Here is a simple circuit switches on a light around 2 hours after midnight, the time at which most of the robberies taking place. This simple circuit is build around a CMOS IC 4060 to obtain the required timing. During day time the LDR has low resistance and keeps the pin 12 of the IC1 high, preventing the IC1 from oscillating. When it is dark the LDR resistance becomes high and the pin 12 of IC1 becomes low...
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12V Lamp flasher circuit.

admin April 7, 2010 3 Comments
Description. Here is a simple yet powerful circuit that can be used for flashing 12V lamps especially that is used on automobiles.The flashing circuit is based on transistor Q1(BC557) and MOSFET Q2 (IRF530) where the Q2 provides the necessary drive for the lamp.Any number of bulbs can be flashed using this circuit provided that the total load must not exceed 42 Watts. Circuit diagram with Parts list. Notes.  Assemble the  circuit on a good quality PCB or common board....
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