# Fundamental Units

• Ampere (A): This is the basic unit of electric current in the International System of Units (SI).
• Tesla (T): This is the standard unit for magnetic flux density or magnetic field strength in SI.

# Derived Units

• Weber (Wb): The SI unit of magnetic flux, which is a measure of the total magnetic field which passes through a given area.
• Henrys (H): The SI unit of inductance, which is a measure of the total electromagnetic field created by a change in current.
• Ohm (Ω): The SI unit of electrical resistance. Resistance is a measure of the difficulty to pass an electric current through a conductor.

# Useful Congruence

• Faraday’s Law: The electromotive force (EMF) induced in a circuit is directly proportional to the rate of change of magnetic flux through the circuit. Mathematically, EMF = - d(Φ) / dt. Here, ‘Φ’ is the magnetic flux measured in Weber and ‘t’ is time in seconds.

# Essential Measurement Techniques

• To measure current, we use an ammeter, which is placed in series in the circuit.
• To measure potential difference, we use a voltmeter, which is placed parallely across the components in the circuit.
• The strength of a magnetic field is often measured with a device called a teslameter or gaussmeter, but it can also be determined using the Hall effect.

# Important Conversions

• Tesla to Gauss: 1 Tesla = 10,000 Gauss. Gauss is the unit used in the CGS system of units (Centimeter Gram Second), while Tesla is used in SI.
• Ampere to Coulomb: 1 Ampere = 1 Coulomb of charge passing through a point in the circuit per second. This ties together electrical current with the concept of charge.

Remember to include the correct units in your answers and to be comfortable converting between different units where necessary.