Valves that open and close rapidly under the control of electronic circuits are:

Valves that open and close rapidly under the control of electronic circuits are:
 
  A) Pulse modulated valves. B) Cross charged expansion valves.
  C) Electronic expansion valves. D) Stepper motor valves.

 Q. 2

One disadvantage infrared thermometers is that they:
 
  A) Are only available in limited quantities due to their specialized nature.
  B) Are generally less accurate than dial type pocket thermometers.
  C) Take longer to get a reading than other types of thermometers.
  D) Can only read the temperature of objects.

 Q. 3

The operation of a thermostatic expansion valve can best be described as:
 
  A) Spring pressure = bulb pressure + evaporator pressure.
  B) Bulb pressure = evaporator pressure + spring pressure.
  C) Bulb pressure = evaporator pressure = spring pressure.
  D) Evaporator pressure = evaporator pressure + bulb pressure.