robotics

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Ohm’s law

states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperatures remain constant.

**VOLTAGE**

is the difference in charge between two points

**CURRENT** (I)

is the rate at which charge is flowing.

**RESISTANCE**

is a tendency of a material to resist the flow of charge (current).

direct current voltage (DC)

Voltage that travels in a straight line.

direct current voltage (DC)

Commonly produced by sources of stored energy like batteries

Sources of DC Voltage

This have positive and negative terminals

resistor

It is the opposition to the flow of electrons.

**Alternating current voltage (AC)**

Reverses direction at regular intervals.

**Alternating current voltage (AC)**

Commonly produced by utilities via **generators**, where mechanical energy—rotating motion powered by flowing water, steam, wind, or heat—is converted to electrical energy.

Voltage

It is the energy used or gained across two points in a circuit.

current flow

What flow is a combination of electron flow and hole flow through a circuit?

electric **current**

 is a flow of electric charge. In electric circuits this charge is often carried by moving  electrons in a wire.

**POLARITY**

It refers to the positive (+) and negative (-) charges that describe the current flow in an electrical circuit.

**POLARITY**

shows the path of the current. Negative charges pass on the negative path and positive charges on positive paths.

RESISTANCE

measure of opposition to current flow in an electrical circuit

**Alternating current voltage (AC)**

direct current voltage (DC)

Voltage

Resistance

Current (I)

” volt drop “.

Voltage is commonly referred to as its

the voltage will produce a current flowing around the circuit.

What will happen when a voltage source is connected to a closed loop circuit?

\+ve

What is the symbol for positive in DC voltage?

−ve

What is the symbol for negative in DC voltage?

Volts (V)

Voltage is measured in?

E

What is the symbol for electrical charge

Current (I)

the continuous and uniform flow of charge around the circuit

Current (I)

measured in Amperes or Amps and has the symbol I

Current (I)

what is directly proportional to Voltage?

Georg Simon Ohm

described the mathematical relationship between electrical current, resistance and voltage

The effective (**rms**) value of an alternating current

has the same average power loss equivalent to a direct current flowing through a resistive element

Conductor

Low values of resistance imply?

insulator

high values of resistance imply?

Current (I)El

What is inversely Proportional to Resistance?

Resistance (Ω or R)

is measured in Ohms

Resistor

are electronic components that limit the current with some value of resistance

Resistance

Blocks the flow of electricity

the little flow of electricity and vice versa

Bigger value of resistance?

Circuit

circular path, which is always required to get electricity to flow and do something useful

Circuit

a path that starts and stops at the same place

SIMPLE CIRCUIT

SIMPLE CIRCUIT

If we connect the positive side of a voltage source, through something that does some work such as a Light Emitting Diode (LED), and back to the negative side of the voltage source; electricity, or current will flow.

SHORT CIRCUIT

if you connect a wire directly from the positive to the negative side of a power supply, you'll create what?

SHORT CIRCUIT

CLOSED CIRCUIT

a circuit without interruption Links to an external site., providing continuous Links to an external site. path Links to an external site through which a current can flow.

OPEN CIRCUIT

The opposite of a short circuit which where the loop isn't fully connected (and therefore this isn't really a circuit at all)

BREADBOARD

used to make up **temporary circuits** for testing or to try out an idea.

holes

Breadboards have many tiny sockets which arranged on a 0.1" grid called?

Integrated Circuit(ICs)

inserted across the central gap with their notch or dot to the left.

**Breadboard with temporary circuit**

light-emitting diode (LED)

is a semiconductor light source that emits light when current flows through it.

Diode

allows current to flow in only one direction

cathode pr negative (-) lead

Larger metal component inside of case or case flat spot is

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PARTS OF LED

Flat spot

Anode

Cathode

The three parts that you need to know when working with LED

Flat spot

it is where the cathode or short leg located

Anode

the positive and long leg of the LED

Cathode

the negative and short leg of the LED

a lamp type (leaded)

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a chip type (surface mount)

Two types of LEDs are available

Lamp type and chip type

LEDs

are diodes which are elecronic devices that only allow current to go through them in one direction

Because diodes are made of semiconductor material, they have a very specific voltage where they will turn on. If the supply voltage you’re using is more than then turn on voltage, you need a resistor between one of the LED leads and the connection to either **GND** or the supply voltage.

LED resistor

The amount of resistance needed depends on how much current the LED will use to be bright enough to see but not so much that it burns itself out. This is usually about 20 milliamps for most single color LEDs. To choose the right amount of resistance for the LED, you also need to know what its turn on voltage (Vf) is. A red LED uses the least amount of voltage to turn on, about 1.8 v while some blue LEDs need more than 3.0 v.

REMEMBER THIS!

The way to decide how much resistance you need, you need to use Ohm’s law for the current through the resistor. (AKA THE FORMULA FOR LED RESISTANCE)

Resistor Voltage = Supply Voltage - LED Turn On Voltage (Vf)

calculate the resistance needed for a 20 milliamp current for a red LED with Vf of 2.0 v

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Resistor Voltage = Supply Voltage - LED Turn On Voltage (Vf)

R = (3.3 volts - 2.0 volts) / 0.02 amps = 65 ohms

RESISTORS: TYPES AND PACKAGE STYLES

COLOR CODE

resistors are labeled with color bands that specify the resistor's nominal value.

The nominal value is the resistor's face value

MEASURED VALUE

A digital multimeter can measure the resistor's actual resistance value

PARALLEL CIRCUIT CONNECTION

an electrical connection that has two or more paths for the current to flow in which the loads are parallel to each other.

PARALLEL CIRCUIT CONNECTION

SERIES CIRCUIT CONNECTION

an electrical connection that is connected along a single path where the current flows in the same direction.

SERIES CIRCUIT CONNECTION

It has only one path to follow with only one load. THE GREATER NUMBER OF RESISTORS, THE LESSER THE ENERGY WILL PASS THROUGH IT

SERIES CIRCUIT CONNECTION