Electrical / Electronic Basic Facts and Laws
- Hydrogen is the simplest element with a single electron in orbit
around a core of one proton.
- The most complex element is uranium with 92 electrons in orbit around
a core of 92 protons.
- Elements with less than four electrons in their outer rings are good
conductors.
- Elements with more than four electrons in their outer rings are good
insulators.
- Elements with exactly four electrons is a semi-conductor.
- The speed of light is 6.28 billion miles per hour.
- Conventional Flow theory states that flow of electrons is from positive
to negative.
- (Accepted in the transportation industry)
- (Accepted in the transportation industry)
- Electron Flow theory states that the flow of electrons is from negative
to positive.
- (Accepted in the electronics industry)
- (Accepted in the electronics industry)
- Electric current creates its own magnetic field around the wire.
- Magnetic lines have direction and change direction when the current
flow changes in the wire from one direction to another.
- As current increases the field strengthens.
- The Hall Effect switch emits a voltage signal from the presence or
absence of a magnetic field contacting a semiconductor material.
- Voltage is the force that causes current to flow through an electrical
conductor.
- Voltage is often referred to as the potential or force and is measured
in volts.
- Voltage can be generated mechanically or chemically.
- Current (amperes) is the flow of electrons through a conductor.
- Current is measured in units of amps.
- One ampere equals 6.28 billion billion electrons per second.
- Current is the amount or volume of electricity in the circuit.
- Resistance is the opposition to the flow of electrical current by
the conductor through which it is passing.
- Resistance is measured in units called Ohms.
- All conductors offer some type of resistance to the flow of current.
- One ohm is the resistance that will allow one amp to flow when potential
is one volt.
- There are 5 parts to the basic circuit, the power source, a protection
device, a control, (switch) a load, and the ground path.
- Circuit types include series, parallel, and series parallel.
- Series circuits.
- Have high circuit resistance
- More than one load
- One path for current flow
- Parallel circuits
- Have low circuit resistance
- More than one load
- More than one current path
- Series Parallel circuits
- Have more than two loads
- Some loads are connected in series
- Some loads are connected in parallel
- Series circuits.
- Multimeters will display four digits.
- Many values that are measured will have more than four digits.
- Multimeters use metric prefixes to reduce the number of digits to
the maximum of four.
- Metric prefixes used are
- Mega (M) = 1,000,000 ( the decimal point is six places to the right)
- Kilo (K) = 1,000 ( the decimal point is three places to the right)
- Milli (m) = .001 (the decimal point is three places to the left)
- Micro (u) = .000001 (the decimal point is six places to the left)
- Examples of metric prefixes converted to actual values
- 3.3M ohms = 3.3 X 1,000,000 or 3,300,000 ohms
- 5K ohms = 5 X 1,000 or 5,000 ohms
- 10.3 m Amps = 10.3 X .001 or .0103 Amps
Basic
Facts and Laws Worksheets