ELECTRONIC AND ELECTRICAL COMPONENTS
Component 1 is a Resistor -- the schematic symbol is a line coming in on each side with a "zig-zag" pattern going up and down.
In general, a resistor schematic symbol will start with a short line in the center, followed by a diagonal line slanting up to the right and a continued "zig-zag" pattern for usually 3-4 lines, with the last one coming up from the bottom back to the center line point and continuing on.
Schematic Symbols are a shorthand to make it easy to recognize the components in a circuit diagram. The circuit diagram is a "map" of the circuit.
The other components on the diagram are:
- 2 - NPN transistor
- 3 - Lamp
- 4 - Battery
- 5 - Ground (chassis ground specifically)
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Component 2 in is a transistor.
A transistor is a control element and has three terminals. The one on the left is called the base. It is the control input and is similar to pushing the gas pedal on your car; the little amount of power your foot puts into pushing the pedal creates a larger amount of power to come from the engine.
The upper right terminal is the collector and has current flowing into it in proportion to the current into the base multiplied by the gain of the transistor (also called hfe or beta).
The lower right terminal has an arrow that indicates the direction the current will flow from both the base and the collector.
Schematic Symbols are a shorthand to make it easy to recognize the components in a circuit diagram. The circuit diagram is a "map" of the circuit.
The other components on the diagram are:
- 1 - Resistor
- 3 - Lamp
- 4 - Battery
- 5 - Ground (chassis ground specifically)
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Component 3 in figure T-1 is an incandescent lamp. The small looping line inside the border shape represents the filament inside the lamp. Current flowing through the circuit causes the filament to glow and emit light.
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Component 4 is a battery.
This is the energy source to power the lamp when a voltage is applied to the input of the circuit. The symbol has one or more sections indicating a number of cells (piles) in the battery pack. The longer line represents the positive terminal while the shorter line is the negative terminal.
Schematic Symbols are a shorthand to make it easy to recognize the components in a circuit diagram. The circuit diagram is a "map" of the circuit.
The other components on the diagram are:
- 1 - Resistor
- 2 - Transistor
- 3 - Lamp
- 5 - Ground (chassis ground specifically)
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A capacitor consists of two conductors (wires, plates, etc) separated by an insulator (such as air). If you look at figure T2 you will see that a capacitor has the symbol of two lines (one usually curved to indicate which side it is, or in other words indicate the polarization of the capacitor) with a gap between.
A capacitor is made up of two conductors with an insulator between them; they are often rolled up, which is why you often see them as a cylinder. The symbol represents that, with each line being a conductor and the gap between being the insulator.
Each line represents a conductor and the gap represents the insulator.
Hint: The [c]urve is a symbol for a [c]apacitor.
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What is component 8 in figure T-2?
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Resistor
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Inductor
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Regulator IC
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Correct AnswerLight emitting diode
The black arrow with a line across the tip (like component 5) is the schematic for a diode; a Light Emitting Diode has essentially the same characteristics of a diode except that it also emits light, therefore the schematic symbol looks like a diode with little zigzag arrows coming out to represent the light waves emanating from the diode.
A list of component schematic symbols can be found here: https://learn.sparkfun.com/tutorials/how-to-read-a-schematic
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What is component 9 in figure T-2?
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Variable capacitor
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Variable inductor
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Correct AnswerVariable resistor
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Variable transformer
A Variable Resistor is easily identified because it looks like a normal resistor (a jagged zig-zag line with straight lines entering and leaving) but with an additional arrow pointing at the middle of the zig-zag perpendicular to the rest of the component symbol. This arrow represents the brush or connection on the variable resistor (potentiometer) that moves when you adjust the resistance.
In the schematic symbol, the two ends have a total resistance between them of the total value of the resistor and the resistance between each end and the middle arrow varies.
A list of component schematic symbols can be found here.
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What is component 4 in figure T-2?
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Variable inductor
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Double-pole switch
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Potentiometer
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Correct AnswerTransformer
A transformer consists of two inductively coupled coils that are not directly connected together. If you look at the symbol you can see the representation of a coil on each side with two lines in the middle to indicate the separation.
A list of component schematic symbols can be found here: Schematic symbols
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What is component 3 in figure T-3?
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Connector
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Meter
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Variable capacitor
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Correct AnswerVariable inductor
The symbol for a variable inductor is similar to that of a potentiometer, with the arrow representing the "wiper" mechanism.
A list of component schematic symbols can be found here (https://www.radioing.com/hamstart/symbols.html).
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The antenna schematic symbol looks a little like the stereotypical "satellite dish"; it's a triangle with one of the points connected to the circuit and the opposite side not connected to anything and a line through the middle. It is usually not hard to remember because it legitimately looks like an antenna =]
A list of component schematic symbols can be found here: Schematic Symbols Also, https://www.ibiblio.org/kuphaldt/electricCircuits/Ref/REF_9.html
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