 | Contactor or relays When a relay is used to switch a large amount of electrical power such as motor, another technical term for relays is contactor. One contactor may have several auxiliary contacts, either normally-open or normally-closed |
 | Toggle Switch Schematic symbol for a single pole, single throw (SPST) toggle switch |
 | Momentary switch Schematic symbol for a single pole, single throw (SPST) momentary switch. Normally opened momentary switch (Mechanical button, horn button in your car) |
 | Normally closed momentary switch Schematic symbol for a normally closed momentary switch |
 | Earth ground - electrical grounding According to National Electrical code(NEC), Voltage to ground- For grounded circuits, the voltage between the given conductor and that point or conductor of the circuit that is grounded. Another way of saying, earth is considered to be at zero potential and establishes a convenient reference frame for voltage measurements |
 | Ground rod example An example practice ground rod, defined by NEC, physically consists of a conductive pipe or rod driven into the earth to a minimum depth of 8 feet |
