If you look at the capacitors on a piece of electronic equipment, you’re likely to see additional numbers. As an example, you may see the number X2A or something similar. These are dielectric codes. There are two types, Class 1 and Class 2.
The first letter in these codes corresponds to the low temperature requirement of the capacitor. X stands for -55°C, Y stands for -30°C and Z stands for 10°C. The second symbol will be a number and it will correspond to the high temperature requirement. Two corresponds to 45°C, 4 corresponds to 65°C, 5 corresponds to 85°C, 6 corresponds to 105°C, 7 corresponds to 125°C and 8 corresponds to 150°C. The third character will be a letter. The letter corresponds to a maximum change in temperature. Those symbols are read as follows:
A: +/- 1%
T: +22%, -33%
U: +22%, -56%
V: +22%, -82%