  Measuring Resistance

The measurement of the resistance is much like the way in which we measure voltage.  Probes are put at two points in the circuits and the probes measure the resistance between the the two points.  Unlike an voltmeter an Ohm meter doesn't need a completed circuit to measure

Ohm Meter

An ohmmeter is an electrical instrument that measures electrical resistance, the opposition to an electric current.  The unit of measurement for resistance is ohms (Ω). Measuring Voltage

The measurement of the voltage is much like the way in which we measure resistance.   probes are put at two points in the circuits and the probes measure the change in potential between the the two points.  Unlike an ohm meter a voltmeter needs a completed circuit to measure

Voltmeter

A voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. Measuring Current

The measurement of the ammeter is much like the way in which we measure voltage.  Like a voltmeter, an ammeter it needs a complete circuit to measure current.

Ammeter

An ammeter is a measuring instrument used to measure the electric current in a circuit. Electric currents are measured in amperes (A), hence the name.

In a simple circuit the the current at every point is equal.  That means the amount of charge leaving the power source is equal to the amount charge entering and leaving a resistors, and equal to the amount of charge returning to the power source.

For any circuit regardless of it configuration is that the voltage at the power source is equal to to all of the potential consumed by the resistors.

example: In the diagram above the potential at the power sources is 12 volts. As the current travels through the resistors (R1, R2, and R3) those 12 volts are consumed by the resistors.  If the resistance in each resistors is the same then each resistors consumes their fair share (4 volts each).  If each resistors different, then each resistor consumes their percent of there total resistance (if one resistors makes up 50% of the total resistance then it would consume 6 volts while the other two have share the remaining 6 volts)