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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3 LED battery monitor circuit

john January 27, 2014 50 Comments
Are you not familiar with the basics of electronics? We have just opened an online store where 4 very good books on basic electronics have been kept for sale. You can read the reviews of these books and buy them as you wish. These books are being followed by students in some of the best universities in the world. Check them out and buy copies here:- 4 GREAT BOOKS TO LEARN BASIC ELECTRONICS Description. This is the circuit diagram of...
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Battery charger using LM350

admin January 18, 2011 10 Comments
Description. Here is a simple circuit using IC LM 350, which can be used for charging 12V lead acid batteries. This circuit is perfect for “constant charging” 12V lead acid batteries. The circuit is designed as a constant voltage source with a negative temperature coefficient. The transistor Q1 (BD 140) is used as the temperature sensor. The transistor Q2 is used to prevent the battery from discharging through R1 when the mains power is not available. The circuit is...
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Battery charger circuit using SCR.

admin November 17, 2011 262 Comments
 Description. A simple battery charger based on SCR is shown here.Here the SCR rectifies the AC mains voltage to charge the battery.When the battery connected to the charger gets discharged the battery voltage gets dropped.This inhibits the forward biasing voltage from reaching the base of the transistor Q1 through R4 and D2.This switches off the transistor.When the transistor is turned OFF,the gate of SCR (H1) gets the triggering voltage via R1 & D3.This makes the SCR to conduct and...
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Battery charger circuit using L200.

admin August 7, 2008 35 Comments
 Description. A very simple battery charger circuit having reverse polarity indication is shown here.The circuit is based on IC L200 . L200 is a five pin variable voltage voltage regulator IC.The charging circuit can be fed by the DC voltage from a bridge rectifier or center tapped rectifier.Here the IC L200 keeps the charging voltage constant.The charging current is controlled by the parallel combination of the resistors R2 & R3.The POT P1 can be used to adjust the charging...
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Battery charger circuit using LM317.

admin August 7, 2008 53 Comments
Description. Here is a simple but effective battery charger circuit using IC LM 317.The circuit can be used to charge 12Vlead acid batteries.The circuit is very simple and can be easily assembled on a general purpose PCB.   The heart of the circuit is IC LM 317 ,which is an adjustable voltage regulator IC.The pin 1 of the IC is the control pin which is used to control the charging voltage.The pin 2 is the output pin at which...
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Broken charger wire alarm circuit

admin June 21, 2008 No Comments
Description. This circuit will produce a visual as well as audible alert whenever the connection between the charger circuit and the battery being charged.What ever be the situation whether it be a  loose contact or breakage the circuit will give you the alarm.Such a circuit can be very handy in the fail safe charging of the batteries in some applications , like as in burglar alarms etc.This circuit can be easily assebled from the components in your electronic junk box. As long as...
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Chager circuit for SMF batteries.

admin June 21, 2008 21 Comments
Description. Here is a simple charger circuit for charging SMF(sealed maintenance free ) batteries.The charger circuit being curernt and voltage regulated,can be safely used to charge SMF batteries of 1.2 AH rating.This circuit was actually designed in response to a request from a reader.With slight modifications you can use it for charging any sort of SMF batteries. The first part of the circuit is the power supply made of transformer T1 and diodes D1&D2.The capacitor C1 filters the rectifier...
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Simple battery charger circuit

admin August 13, 2017 22 Comments
How to make a 12V battery charger at home? Description  Here is the circuit diagram of a simple and straight forward 12 V battery charger circuit with diagram. This circuit can be used to charge all type of 12V rechargeable batteries including car batteries. The circuit is nothing but a 12V DC power supply with an ammeter for monitoring the charging current. The two diodes forms a centre tapped full wave rectifier. The capacitor filters the rectifier output to...
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Super fast Ni-Cd battery charger

admin February 16, 2012 No Comments
Description. Here is  the circuit diagram of an effective and super fast Ni-Cd battery charger circuit.The circuit is based on the IC MAX 712. The circuit is designed to fast charge a Ni-Cd battery at 3oomA. After the fast charging is completed the circuit charges the battery in trickle charging mode at 15 mA. Here the instant to end fast charging and start trickle charging is sensed by dv/dt method as per the data sheet. This method of charging...
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