TABLE OF CONTENTS
CHAPTER ONE
1.0 Introduction
1.1 Types of low power indicator
1.2 Practical examples
CHAPTER TWO
2.0 Circuit diagram of L.E.D Zener P.S.U
2.1 Components of the circuit
2.2 Circuit description
CHAPTER THREE
3.0 Actual construction
3.1 Advantages of using Vero-Board
3.2 Soldering technique
3.3 Soldering Iron
3.4 Precaution taken during construction
CHAPTER FOUR
4.0 Circuit testing and fault finding
CHAPTER FIVE
5.0 Conclusion
Reference
ABSTRACT
A Low Power Indicator is a device that indicates by way of displaying light to indicate the level or strength of electrical power in a given circuit at a particular time. The transistors T1, T2, T3 are low power transistors that control the flow of electron in the circuit VR1 is employed to vary the frequency of the power.
CHAPTER
ONE
1.0 INTRODUCTION
A
Low Power Indicator can be defined as an indicator that is having a very low
electrical supply or current situated in an electrical instrument which
indicates the amount of power present in the instrument by their colour
indication be it red, yellow or green.
1.1 TYPES OF A LOW POWER INDICATOR
A. LIGHT – EMITTED DIODE (LED):
– This is a junction diode made from the semiconductor gallium arsenide
phosphide which has large band gap and hence a larger forward drop than
silicon. Typical flooded panel – type LED indicators look good at 10MA forward
current on a board inside an instrument one can usually get away with 2.5MA,
particularly if one use a narrow-angle LED. When forward biased it emits red,
yellow or green light depending on its exact composition. No conductor or light
emission occurs for reverse bias which if it exceeds 5V, may damage the LED.
B. LIQUID CRYSTAL DISPLAY (LCO):
– This is a display that is usually is a driven by an a.c wave form otherwise their
liquid guts (contents) are ruined. However, it driver chips have some way to
generate a square – wave segment drive, synchronized to the LED backplane wave
form. An example is the HC4543, the LED cousin of the HC4511 LED latch/decoded
driver. LCD come in rather large panels that can display a line or two or text
i.e they have ability to store several message and communicate via serial
ports.
C. LOW – BATTERY INDICATOR USES FLEA POWER:
– This is a low indicator that consumes as little power as possible for a 9V,
450-MAhr alkaline battery, a 50 – PA low battery indication can by itself run
the battery down in a little more than a year battery – powered devices that
need to run continuously for a long time require battery indicators that
consume minimal power.