Digital tube: Handheld digital signal generator features a 4-digit high-definition display with uniform and adjustable screen brightness (levels 1-8). Use: During normal operation, the signal generator simulates a screen display, saving voltage and current values. Press the encoder to save; after releasing the OK button, the screen confirms successful saving. Power supply: The voltage signal generator supports an external DC 15-30V power supply, compatible with the 24V power supply of PLC and other equipment. Offers three power options: external power supply, DC5V micro USB, and built-in lithium battery (only available in model type 1 with lithium battery charging capability). Features: Automatically restarts and displays the previously saved value, eliminating the need to readjust parameters upon each power-on, providing convenient and efficient operation.