Resistor Component's Symbol and Layout?

The symbol of a Resistor, as you can see that it is being label started with letter ''R'' meaning for Resistance and followed by a ''Mounted Code'', that code is the number of that resistor for easy identification and search reason on the whole structure of a PCB board. Then,  also ob-course the Resistance Value for test and check up procedures, like for example ''R4400 = 47K''  it means that Resistor number 4400 connected on that particular circuit's value is 47K  or 47000 ohms. In that way we can easily trace and and test that component using a Multi-meter tester. 



There are two types shown in here, The first one is Fixed Resistor and the other one with a line across to it is called Thermistor or Thermal Resistor.

Thermistor or Thermal resistor is a variable Resistor, meaning it's resistance value is changeable. Thermal defines to heat temperature, it is being change by a current or voltage flowing across to it. It also have a capability to shut off when a voltage or current drive it to a maximum temperature level.
While the Fixed Resistor, remains steady to it's resistance value.