Explanation of the circuit

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• Introduction
• Explanation of the circuit
• Price breakdown
• Construction notes
• Distribute kits
• Build time

http//www.nisk.k12.ny.us/iroquois/teched//Fall_Co
nference/battery_eater/battery_eater.htm
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The Battery Eater

• Giving old batteries a new life

DEADERCELL
NEVERREADY
NEVERLAST
http//www.nisk.k12.ny.us/iroquois/teched//Fall_Co
nference/battery_eater/battery_eater.htm
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Joule Thief
Battery Eater

• The Battery Eater is really two Circuits in one

LED Flasher
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The Joule Thief

• The Joule Thief uses a hand wound transformer to
  increase voltage

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How it Works Joule Thief

• Voltage flows through the left coil, the resistor
  limits current

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OFF
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How it Works Joule Thief

• The transistor turns on allowing a large current
  to flow through the right coil

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ON
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How it Works Joule Thief

• The current in the right coil induces a current
  in the left coil which opposes its existing
  current flow, shutting
• off the transistor.

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How it Works Joule Thief

• Current in the right coil cannot shut off
  immediately leading to a bump in voltage

as the field in the left coil breaks down
Small Voltage rise
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Field breaks down
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OFF
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How it Works Joule Thief

• This process repeats, and the voltage rises

Small Voltage rise
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Field breaks down
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OFF
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How it Works Joule Thief

• Once the voltage reaches the breakdown voltage of
  the LED electricity can flow

Small Voltage rise
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Field breaks down
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OFF
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Turning the Joule Thief on

• Making the joule thief turn on at night and off
  in the morning adds just one extra component

A voltage divider is created by the addition of
the LDR keeping the transistor off when exposed
to light
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LED Flasher

• Two PNP transistors act as switches to turn on
  LEDs

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How it Works LED Flasher

• An RC circuit triggers the transistors

• Changing the resistor and capacitor will
  determine the LED flash rate

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Materials and Kit Cost

• 14 components, 1 single sided PCB

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PCB/Parts Layout
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