WORKSHOP PRACTICE WEEK4 OBJECTIVE OF LAB3 To be

WORKSHOP PRACTICE WEEK-4

OBJECTIVE OF LAB-3 • To be familiar with a light bulb. • To be familiar with the series circuits • To be familiar with the parallel circuits.

ELECTRONS ENERGY • Metal atoms release mostly infrared light photons, which are invisible to the human eye. • But if they are heated to a high enough level around 4, 000 degrees Fahrenheit or (2, 200 degrees C) in the case of a light bulb -- they will emit a good deal of visible light.

CIRCUIT • The configuration of electric components and active sources such that there is a flow of current is called an Electric Circuit.

SERIES CIRCUITS

PARALLEL CIRCUITS

LIGHT BULB • A light bulb, or electric light or electric lamp is a device that produces light from electricity. • In addition to lighting a dark space.

APPLICATION OF LIGHT BULB It will be used as follows: » Indicator » To direct traffic » Status of electronic circuits » Or many other applications

LIGHT BULB STRUCTURE

fluorescent lamp • A fluorescent lamp, or fluorescent tube, is a lowpressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the lamp to glow.

A preheat fluorescent lamp circuit using an automatic starting switch. A: Fluorescent tube, B: Power (+220 volts), C: Starter, D: Switch (bimetallic thermostat), E: Capacitor, F: Filaments, G: Ballast

• This technique uses a combination filament– cathode at each end of the lamp in conjunction with a mechanical or automatic (bi-metallic) switch (see circuit diagram to the right) that initially connect the filaments in series with the ballast to preheat them; when the arc is struck the filaments are disconnected. This system is described as preheat in some countries and switchstart in others. These systems are standard equipment in 200– 240 V countries (and for 100– 120 V lamps up to about 30 watts

Energy Saver (Compact Fluorescent Lamp) Electronic Blast Circuit

• Fluorescent lights make their light energy in a three-step process: • Electrodes take electrical energy from the power supply and generate moving electrons. • The moving electrons collide with mercury atoms in the tubes to make ultraviolet light. • The white phosphor coating of the tubes converts the ultraviolet light into visible light (that we can see).

SERIES & PARALLEL CIRCUITS ANIMATION • http: //www. physics-chemistry-interactive-flashanimation. com/electricity_electromagnetism_intera ctive/components_circuits_associationseries_parallel. htm

SHORT CIRCUIT ACTIVITY • http: //www. physics-chemistry-interactive-flashanimation. com/electricity_electromagnetism_intera ctive/short_circuit_an_activity. htm

WHY SHORT CIRCUIT IS SO DANGEROUS ? • http: //www. physics-chemistry-interactive-flashanimation. com/electricity_electromagnetism_intera ctive/short_circuit. htm

HOW TO DRAW A SIMPLE CIRCUIT DIAGRAM • http: //www. physics-chemistry-interactive-flashanimation. com/electricity_electromagnetism_intera ctive/circuits_diagram. htm

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