Circuit Components Reference

Conductor – anything that allows electricity to travel through easily. For example: electrical wires and most metals.
Insulator – anything that stops electricity from traveling. For example: most plastics, glass, rubber.

wirewire2

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Resistor – an electronic component that allows only some electricity to travel through, blocking the rest.

This is a symbol for resistor in circuit diagrams: 2000px-Resistor_symbol_America.svg

Resistance is measured in Ohms.

Resistance is often marked on a resistor using a color code:

Resistor_color_codes

For the resistor at the bottom

First band is Red: 2    Second band is Orange: 3    Third band is Violet: 7     Fourth band is Black: x1

237 X 1 = 237

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Diode – allows electricity to travel in one direction only.
This is a symbol for diode in circuit diagrams:diode

The big arrow points to the direction of electricity flow.

 

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LED Light Emitting Diode  – allows electricity to travel in one direction only, emits a light while doing it.
IEC_LED_SymbolThis is a symbol for LED in circuit diagrams.

The big arrow points to the direction of electricity flow.

The little arrows are emitting light.
LEDs come in different colors and sizes.

leds

Note that one leg of an LED is longer than the other.

led2

This leg is called the anode or the positive leg, the short leg is called the cathode or the negative leg.  Electricity flows in one direction only: from the anode to the cathode, or from the positive leg to the negative leg.

WARNING

NEVER CONNECT AN LED DIRECTLY TO A POWER SOURCE

AN LED REQUIRES A RESISTOR TO OPERATE

OTHERWISE AN LED MAY BE PERMANENTLY DAMAGED

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Motor – motors convert electrical energy to physical energy. They spin and can do work when electrical power is applied to them.

symbol_motor This is a symbol for motor in circuit diagrams.

 

 

Regular electrical motors will spin as long as they have power connected.  They can spin forward or backward depending on electrical connection.  To spin motor the other way, simply switch positive and negative connections.
Motors can be very largeRefurbished electric motor

 

 

 

 

 

or very small: smallmotor

 

 

 

 

 

 

WARNING

    NEVER CONNECT A MOTOR DIRECTLY TO RASPBERRY PI GPIO PINS
YOUR RASPBERRY PI MAY BECOME PERMANENTLY DAMAGED
MOTORS SHOULD BE CONNECTED ONLY TO A MOTOR OR ROBOTIC CIRCUIT BOARD (HAT) OR TO A TRANSISTOR

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Transistor – an electronic component that can act as an amplifier or a switch.

When used as an amplifier, transistor takes small electrical current and boosts it to a larger electrical current.

When used as a switch, transistor allows electrical current to flow and power a device when electrical current is applied to one of its terminals.
1024px-Transistor.symbol.npn.svg Electrical diagram circuit symbols for transistor.

 

Single Transistor

SC-PNP-2N2907_LRG

 

 

 

Transistor Array bipolar-transistor-module-mosfet-bipolar-33744-2258607————————————————————————————————————————————-

Stepper Motor  – this motor can spin just like a regular motor, but it can also move by using “steps” – predefined intervals.

stepperThis is a symbol for stepper motor in circuit diagrams.

 

Stepper motors can spin forward and back, as well as stepping forward and back.  Step size is determined by the internal gearing of the motor.

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