Digital tube: handheld digital signal generator includes the 4-digit high-definition tube, the screen brightness is uniform and adjustable (1-8 brightness)Use: In the signal generator normal operation screen simulation, saving a voltage and the current value, Cilck the encoder to save, after releasing the OK button, the screen displays , which means the saving is successful Power supply: voltage signal generator has a external DC 15-30V power supply, which can share the 24V power supply of PLC and other equipment. Three power supply methods: There is an external power supply, DC5V micro USB, Bulit-lithium battery (only if you choose type 1 can bulit you in lithium battery charging mode)Features: Restart directly display the saved value, no need to adjust the parameters every time when you turn on the signal generator, which is very convenient.