 Although modern cathode-ray tubes used in televisions and computer displays have epoxy-bonded face-plates or other measures to prevent shattering of the envelope, CRTs must be handled carefully to avoid personal injury.To accelerate the electrons from the cathode to the screen with sufficient velocity, a very high voltage (EHT or extra-high tension) is required, from a few thousand volts for a small oscilloscope CRT to tens of kV for a larger screen color TV.This is many times greater than household power supply voltage.