Fundamentals of Electricty
Alternating Current (AC) is current that?
What is current that Alternates its direction of flow through the conductor
What do transformers enable HVAC technicians to do safely?
Work on equipment by lowering voltage from line voltage to low voltage
A ladder diagram is?
A symbolic representation of circuit logic
The control board in an HVAC system is often called?
he brain of the system
The refrigerant cycle in HVAC is compared to?
The circulatory system
What is a cycle in AC current?
The period of time required for voltage to peak in both directions and return to 0V
What does a step-down transformer do?
Decreases voltage
In a ladder diagram, L1 and L2 represent?
Line voltage rails, with L1 on left and L2 on right
The control board's primary function is to?
Receive signals from thermostats and sensors, then send commands to components
The electrical system in HVAC is compared to
The nervous system, sending signals to control every action
Direct Current (DC) is defined as?
A continuous flow of electrons in one direction
Three-phase transformers are typically used in?
Larger commercial and industrial applications
A high-pressure switch is used to?
Shut down the system when pressure exceeds safe levels
A relay functions as?
An electrically operated switch using low-voltage signal to energize high-voltage components
HVAC technicians must be proficient in working with?
Both low-voltage and line voltage systems
Before using a multimeter, you should?
Check for visible damage to leads and ensure probes are in good condition
Which equipment uses transformers?
Furnaces, air conditioners, heat pumps, air handlers, package units, and zone boards
Do ladder diagrams show the actual physical route of wires?
No, they show circuit logic
A condensate float switch activates when?
The condensate drain is clogged
Which safety procedure is critically important when servicing HVAC equipment?
Lock-out/tag-out procedures
What safety gear should be worn when using a multimeter with high voltages?
Insulated gloves and safety goggles
A transformer is a device that?
Transfers electrical energy between circuits
In schematic diagrams, heavy lines typically represent?
Line voltage
Sensors are compared to what in relation to the control board?
The eyes and ears
Why should you never assume power is off to equipment?
Electrical panels may be mislabeled or someone may have worked in the panel