DC-DC Converter Module. Application Circuit 6

This is an excellent DC- DC Converter Module that can adjust the output voltage to any desired value, even fractions from 0 V to 17 V. It is a very good Variable Power supply Module. But pressing the switch we can adjust the output voltage. It can handle a Peak current of 3 Amps. The output voltage and current are displayed in an LCD Screen that has back light. If the input voltage is from a Battery, the LCD display shows the Battery Level also.  Input voltage can be between 5V and 23 V but the best voltage is 20 V. It has 95% conversion efficiency and 1% LCD accuracy. It is available with a transparent casing. You can fix it in the case provided along with the Module.It can be connected to the Bread board so that we can determine the current consumed by the project.  Its cost is just Rs.350.
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Portable Power supply. Design Note 44

Hacked my Laptop battery and charger to make a Portable power supply. My old Laptop was irreparably damaged leaving only a good battery. It is a high performance 12 volt Lithium Ion rechargeable battery that can backup more than 2 hours a laptop and many hours for circuit boards and LED lights. So I made a Portable power supply using the battery. So don’t discard the battery and charger if your Laptop fails permanently. Both battery and the charger costs around Rs. 2000.It can be utilized for making a Power supply or LED lamp. So it is the  good power supply I ever made because it is running on battery and output is fully regulated.
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Solar Power Supply. Design Note 15

IMAGEYou can make this Solar Power supply as your work bench power supply for testing prototypes. It delivers variable voltage from 1.5 volt to 12 volts with a current up to 300 milli amperes. It can also be used to charge batteries during day time. By using the Pot, it is easy to set the output volt from 1.5 to 12 Volts.
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Simple Variable Power Supply. Design Trick 15

You can make a simple Variable Power Supply unit with two Transistors and a Pot. Two high power complementary transistors are used in the circuit to handle high current. Just provide 14 volt DC to the input and adjust a Pot to get 1 to 12 volt DC from the output. It is useful to power circuits while testing.

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Tristate Battery Level Indicator

Here is a simple but useful battery level indicator to monitor the battery terminal voltage.Efficiency of the battery reflects in its terminal voltage. A good Lead Acid battery will show 13.8 volts in the fully charged state and if it is below 10 volts, the battery needs immediate charging. If the battery voltage goes above 14 volts, it is in the overcharged condition. This circuit uses a two lead bicolour LED to indicate three battery levels. If the voltage is below 10 volts, the Green part of the LED lights and if the voltage is above 14 volts, the Red part lights. If the battery voltage is between 10 to 14  volts LED remains off.

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