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Introduction to Electronics. Basic Electrical Circuits Basic Units Safe Levels Voltage Current Unit prefixes Measuring Devices The Tester Breadboard. Lesson 1 . Basic Electrical Circuits Basic Units Safe Levels Voltage Current Unit prefixes Measuring Devices. Random Movement.
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Introduction to Electronics Basic Electrical Circuits Basic Units Safe Levels Voltage Current Unit prefixes Measuring Devices The Tester Breadboard
Lesson 1 • Basic Electrical Circuits • Basic Units • Safe Levels • Voltage • Current • Unit prefixes • Measuring Devices
Random Movement Electron Flow Electricity An electric current is produced when electric charges move in one direction It is measured either in Voltage and Amps
- + Component Circuits Currents require complete conducting paths. These paths are called circuits wires are used to connect components Battery
Circuits • Every circuit requires these three things: • Power Source • Load • Conductor (wire) • A circuit may include a “control device” such as a switch
Circuits Some of the components you will be using are Battery, resistor, capacitor, Integrated Circuits, L.E.D.
The Three Main Quantities • Voltage, symbol - V, units - Volts • Provides the “push” • Current, symbol - I, units - Amperes (Amps) • Flow of Electrons • Amount of Current is dependent on Voltage and Resistance • Resistance, symbol - R, units - Ohms (Ω) • Limits the amount of current • Represents the “load” of the circuit
Safe Levels • Voltage: 30 V • Voltages inside a computer do not exceed 12 V, except at the power supply and power switch, which could be at 120 V, depending on computer style. Be careful in these areas! Do not attempt to open monitors! • Current: 5 mA (0.005 Amperes)
Voltage Can Be Provided From… • Voltage Regulator 7805 • a battery – 9V Converts 9V to 5V • a conventional power supply • a computer power supply Red: 5V Yellow: 12V Black: Ground
Current • …is simply the flow of electrons • Direction depends on convention • Electron flow is from (-) to (+) (flow of electrons) • Conventional flow is from (+) to (-) (hole flow)
Unit Conversions and Prefixes • Sometimes Volts, Amps, and Ohms are either too big or too small – prefixes are used….
Measurement • Voltage, Current and Resistance are measured using a meter. • We use a Digital Multi-meter (DMM) • Settings need to be adjusted depending on the measurement being performed • You must use the correct setting
AC Voltage DC Voltage DC Current Resistance Diode Check High Current Only Red Lead Common Ground Meters
Voltmeter Measuring Voltage Use the meter to measure across a component (in parallel) e.g. a battery
Ammeter (current) You use an ammeter to measure current You put the meter inline with the component (in series)
Resistance You measure resistance across a component
Questions • Convert the following: