How to make a Mini Power Bank

Don’t throw away the old Mobile battery. The high efficiency Lithium Ion battery can be reused to make a Mini Power bank useful as a Travel Mobile charger. For this, you needs a Lithium battery charger Module and a Mobile charger module in addition to the battery. Both modules will cost around Rs.100.
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How to determine the voltage level in Lithium Ion battery

Lithium Ion batteries are now widely used in Mobile phones, Power banks, Digital cameras and other devices that requires 3.6 V . Lithium Ion batteries are long lasting since its current rating is very high above 2300 mAh.It is very important to maintain Lithium Ion batteries since, both over charging and poor charging may completely destroy the battery.Some have the habit of plugging the Mobile phone in charger overnight. Mobile battery needs to be charged only when its charge goes below 50 %.Proper charging and discharging increases the life of Mobile battery and its efficiency. Let us see its voltage levels
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How to Convert SMPS to Bench Power supply cum charger

Don’t throw away the SMPS power supply when the Computer damges. SMPS is a high current device that gives different regulated voltages from the output wires. It has numerous wires to give different voltages . So you can make a good Multi voltage power supply for the Projects or use as battery charger for different types of batteries. It has total isolation from Mains and output is safe DC.
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Simple LED Volt Meter

A simple LED Volt Meter using Zener diodes as switches. If it is connected to a 12 Volt battery it shows the following indications.


Flash LED Blinks – Above 13 volt – Fully charged
Green LED lights – Above 11.8 V
Yellow LED lights – Above 11.5 V
Red LED lights – Above 10.6 V

If all LEDs light, battery voltage is above 13 volt and fully charged

Hacking a Remote. Application Circuit 3

remote-5We construct different types of Infrared Receiver LED ( Rx) or IR Sensor ( TSOP 1738 ) based circuits. To test, the working of the circuit we have to use an IR Transmitter. Usually we use IC 555 based IR transmitter for this. But the frequency of the IR from the Transmitter should match with that of the Sensor, otherwise the circuit will not respond. Here is a simple solution to test the IR based circuits. Simply Hack a Mini Remote obtained along with low cost FM radio, Toys etc. You have such Remotes in your Junk box. Let us Hack one such Remote to make a Tester.
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Car USB Charger using MC 34063. Start Up Project 40

usb-charger2So many types of Car USB chargers are available which step down the 12 volt DC from the Car battery to 5V DC for charging devices like Mobile phone, Tablets, MP3 player etc. These are usually connected to the Lighter socket to get 12V. The low cost chargers do not have a circuit inside but simply providing 12V DC directly. Only a fuse is present in it. This is dangerous because, the Car battery is a high current one which can damage the gadgets. Here is a simple solution for this. We can make a Voltage and Current regulated Car Charger using the IC MC 34063. It is a Step down DC – DC Converter IC with many features. The output from the circuit will be 5 V at 500 mA.

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LED Indicator for Emergency Lamp. Start Up Project 39

charge-indicator-2-aMost of the low cost LED Emergency lamps do not have LED indicators to show charging and load on conditions. This simple circuit solves the problem. It can be hooked in the Emergency lamp. A Green LED lights when the charging is going on and turns off when the charger is disconnected or power fails. It gives a good indication that current is flowing to the battery. A Red LED lights when the load turns on. It also indicates that charging process stopped.
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