Thermostat schematic symbols represent the various electronic components that comprise the thermostat's electric circuit. Line connectors between symbols depict the connections between the electronic components by wires or printed circuit board contacts.
Thermostat schematics typically use standard schematic symbols for electronic components. Many different electronic components and type variations of components are included in a thermostat's circuit and are represented in the associated schematic.
A resistor is represented as a short zigzag line segment. Resistors oppose the flow of electrical current and can be used to limit the current flowing through another electronic component in the thermostat. A capacitor is represented as two parallel lines, often with one line curved. Capacitors store and release electric charge over brief periods, and they can be used to help smooth variations in electrical current within the thermostat control circuit.
A transformer is represented as two adjacent parallel lines with curved humps on each side. Transformers shift electrical voltage from one value to another, such as shifting 110 volt household current to a lower voltage that is required by the thermostat's control circuit. The transistor is represented as a pi-like symbol and an arrowhead, which is enclosed in a circle. A transistor accepts a low level of voltage to control a larger value of current that flows through the transistor contact points. A transistor can be used to boost or amplify tiny electrical signals, such as those from a temperature sensing component, so that the thermostat's other electronic components can be activated or controlled.