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Light Up Simple LED with Weak 1.5V Battery and Joule Thief Circuit

This easy LED circuit with Joule Thief can make light from weak 1.5V battery!

It work with white, blue and UV LED.

We just need low power battery like 1.2V.

Nice thing is LED still glow even if battery is very low like 0.4V.

Now we can use old battery which people throw away!

WARNING: Making circuit can be dangerous.

Do only under the help of big person or experts.

What is a Joule Thief Circuit:

Joule Thief circuit is small voltage booster and it can take weak battery and make power strong again.

The idea is simple which uses few parts to make low battery and to give more power.

Even if battery is almost dead it still can run small things with this circuit.

Circuit Diagram:

Parts List:

ComponentDescriptionQuantity
Resistor1/4 W CFR 1k1
CapacitorCeramic 100nF1
SemiconductorsTransistor BC5471
Battery 1.5V AAA Cell1
LED 5mm 20mA1
Transformer As explained in article1

Formulas and Calculations:

Coil Turns (N): N = 2 × 50 turns

Make two coil winding each 50 turn.

Coil Wire Thickness (d):

Wire size: 0.05 mm to 0.2 mm

Use thin copper wire like hair.

Ferrite Core Area (A):

A = 7 mm² Middle part of coil is 7 mm².

Work Frequency (f):

f = around 50 kHz Circuit works at high speed like 50,000 times in 1 second.

Construction of ferrite core:

Coil Winding:

Core Assembly:

Circuit Connection:

Frequency Adjust:

Capacitor (Optional):

Enclosure Making:

Power Source:

Voltage Idea:

Working Frequency:

Safety Tips:

Conclusion:

This Light Up Simple LED with Weak 1.5V Battery and Joule Thief Circuit is smart way to use weak batteries, even battery people think is dead it can still glow LED!

Steps and parts in this post help to make it easy.

References:

Joule thief

Joule Thief and its Applications

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