Podcast
Questions and Answers
______ volume control or replace volume control.
______ volume control or replace volume control.
Clean
What should be done if the loud speaker has clear sound when using an earphone?
What should be done if the loud speaker has clear sound when using an earphone?
Noise is being heard with all stations. The turning capacitor plates are rubbing.
Noise is being heard with all stations. The turning capacitor plates are rubbing.
True
What should be checked before replacing a new transistor when only one station is being heard?
What should be checked before replacing a new transistor when only one station is being heard?
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What does the 'CAUTION' symbol indicate?
What does the 'CAUTION' symbol indicate?
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What does the 'SAFETY ALERT' symbol suggest?
What does the 'SAFETY ALERT' symbol suggest?
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Direct current varies periodically in polarity.
Direct current varies periodically in polarity.
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______ is used to represent various electrical devices in a diagram or plan of an electrical circuit.
______ is used to represent various electrical devices in a diagram or plan of an electrical circuit.
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Match the following electronic symbols with their descriptions:
Match the following electronic symbols with their descriptions:
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What does a 'DANGER' symbol specify?
What does a 'DANGER' symbol specify?
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What tool is used to shrink plastic tubing to protect exposed wire?
What tool is used to shrink plastic tubing to protect exposed wire?
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Which component is used to limit the current flow in a circuit?
Which component is used to limit the current flow in a circuit?
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A light-emitting diode (LED) emits light when electricity flows through it.
A light-emitting diode (LED) emits light when electricity flows through it.
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Biasing is the process of providing a desired voltage (bias voltage) to a component or circuit. The two methods of biasing a diode are Forward Biasing and ___ Biasing.
Biasing is the process of providing a desired voltage (bias voltage) to a component or circuit. The two methods of biasing a diode are Forward Biasing and ___ Biasing.
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Match the Radio Receiver function with its description:
Match the Radio Receiver function with its description:
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Study Notes
Electrical Signs and Symbols
- Electrical signs and symbols are used to represent various electrical devices in a diagram or plan of an electrical circuit.
- Warning icons are used to alert users to potentially hazardous conditions and instruct them on how to avoid them.
- There are different types of warning icons, including:
- Caution: indicates precautionary measures against potential hazardous situations.
- Safety Alert: indicates that a person should observe extra awareness.
- Prohibition: indicates that a specific activity is not allowed.
- Danger: specifies a hazardous situation that can result in serious injury or death.
- Warning: specifies a potentially hazardous situation that can result in serious injury or death.
- Read and Understand Instruction Manual: indicates that a person should read the manual before using a device.
- Wear Eye Protection: indicates that a person should wear safety goggles or eye protection.
- Electrical Hazard: indicates that an electrical hazard is present in the area.
- Voltage Danger: indicates high voltage in the area and surrounding equipment.
Electrical Symbols
- Electrical symbols are small drawings or pictograms used to represent various electrical devices in a diagram or plan of an electrical circuit.
- Examples of electrical symbols include:
- Conductor/Wire
- Terminal
- Switch
- Fuse
- Connected Wire
- Circuit Breaker
- Cell
- Battery
- Resistor
- Capacitor
- Diode
- Ground
- Lightning Arrester
- Kilowatt-hour meter
- Power Panel
- Lighting Panel
- Incandescent Bulb/Fluorescent Lamp
- Junction Box
- Main Distribution Panel
Fundamentals of Electronics
- Electronics technology involves the control of electricity in a vacuum or solid conductor materials.
- Sources of electricity include:
- Static Electricity by Friction
- Conversion of Chemical Energy
- Ions
- Electromagnetism
- Photoelectricity
- Thermal Emission
- Doping of Conductors
- Alternating Current (AC) has characteristics including:
- Periodically reversing in polarity
- Signal varying between reversals
- Stepping up or down by a transformer
- Being used as a signal output for an amplifier
- Being easy to amplify
- Direct Current (DC) has characteristics including:
- Having a fixed polarity
- Varying in magnitude
- Not being able to be stepped up or down by a transformer
- Being used for electrode voltages in amplifiers
- Being easy to measure
Soldering
- Soldering is the process of joining two or more terminal wires together permanently with the use of soldering lead.
- Good soldering output depends on the quality of soldering materials, tools, and techniques.
- Soldering tools include:
- Electric Soldering Iron
- Electric Soldering Gun
- Long Nose Plier
- Diagonal Cutter
- Flat Screwdriver
- Philips Screwdriver
- Desoldering Tool
- Volt-Ohm-Milliammeter (VOM)
- There are different types of soldering techniques, including:
- Dip Soldering
- Wave Soldering
- Characteristics of a good solder include:
- Good bonds between the joined metals
- Forming a shiny cover without any air space
- Having flux to remove any oxide film on the metals joined together
Electronic Components
- Electronic components have distinct purposes and functions.
- Examples of electronic components include:
- Resistors
- Capacitors
- Inductors and Coils
- Switches
- Semi-Conductor Devices
- Transistors
- Diodes
- Rectifier Diodes
- Light Emitting Diodes (LEDs)
- Each component has a specific function, such as:
- Resistors: limiting the flow of current in a circuit
- Capacitors: storing electricity and then discharging it back into the circuit
- Inductors and Coils: used in switching to different radio stations
- Switches: interrupting electric current by turning a circuit on or off
- Transistors: amplifying or increasing weak signals
- Diodes: routing electricity from taking an unwanted path within the circuit
- LEDs: emitting light when electricity flows through them
Circuit Analysis
- Circuit analysis involves the study of electronic circuits and their components.
- The power supply is a critical component of an electronic circuit, converting alternating current inputs to direct current outputs.
- Rectifier circuits are used in power supplies to convert AC to DC.
- Types of rectifier circuits include:
- Half-Wave Rectifier
- Full-Wave Rectifier
- Full-Wave Bridge
Printed Circuit Board (PCB)
- A PCB is a board that has conductive paths and components mounted on it.
- The power supply is a critical component of a PCB, converting alternating current inputs to direct current outputs.
- Rectifier circuits are used in power supplies to convert AC to DC.
Operation of a Radio Receiver
- A radio receiver is a device that receives transmitted signals and produces audio form.
- The function of a radio receiver includes:
- Reception: receiving transmitted electromagnetic waves
- Selection: selecting a particular station frequency from all transmitted signals
- Detection: separating the low frequency intelligence from the high frequency carrier
- Amplification: increasing the signal
- Reproduction: producing the original audio signal### Radio Receiver Characteristics
- Sensitivity: ability to reproduce the signal from the weakest station with the same signal output value
- Selectivity: ability to differentiate between desired and undesired signals
Troubleshooting
- Locating, correcting difficulties and improper operations of components in electronic circuits
- Typical radio receiver problems: no audio output, weak output with no excessive background noise, and distorted audio production
AM Radio Receiver Sections
- Power Circuits: most likely to have problems due to heat generated by high currents
- Audio Circuits: include circuits from volume control to loudspeaker; can be tested by touching the high side of the volume control to hear a loud hum or sound
- IF Sections: circuits from mixer output to detector input; timed to 455 KHz in AM and 10.7 MHz in FM for test signals
- RF Sections: include antenna, RF amplification up to mixer input, and local oscillator stage; RF signal frequencies are 535 to 1.605 MHz for AM radio and 88 to 108 MHz for FM radios as test signals
AM Radio Trouble Shooting Chart
- Weak signal only at one end of dial: transistor in converter stage is defective; replace with a new transistor
- Intermittent operation: poor solder joint, break in printed wiring, poor battery contacts, earphone jack has loose contacts, power switch has loose contacts, volume control is dirty, or turning capacitor is dirty
- Distortion in volume control settings: weak battery, leaky or dried out electrolytic capacitors, soldered joint has high resistance, or carbon resistor has increased in value
- Distortion on strong signal only: capacitor is shorted or bypass capacitor is defective
- Squealing or motor boating: weak battery, bypass capacitor is defective, or battery or tuning circuit has high resistance
- Squealing can only be heard when the station is tuned in: weak battery, antenna core is cracked, or defective C4 capacitor
- Only one station is being heard: local oscillator is not working
- Noise is being heard with all stations: turning capacitor plates are rubbing
- When tuning in to different stations, volume changes too fast: converter transistor is defective
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Description
This quiz is about electrical signs and symbols that appear in power tool manuals, and understanding their meanings to ensure safe operation. Learn about the caution and warning icons that help prevent hazardous conditions.
