Power Supply: built-in rechargeable battery ( via -USB port), external -USB-5V, external power DC 15-30V, each way makes the generator work Voltage Output: 0-10V, precision is 0.01V, rotate the encoder knob to adjust output voltage, can be calibrated. Current Output: 0-22mA, precision is 0.01mA, rotate the encoder knob to adjust output current, can be calibrated. Multiple Display: just push the small botton to switch the display mode between voltage and current, you can also follow the instructions to switch 0- or 0-50HZ display. signal generator is designed to 0-10V voltage signal and 0/4-20mA current signal for PLC and panel Debugging, Device Testing, Frequency Converter, Flow Valve, . It can display 4 different types of digit, 0-10V voltage, 0-22mA current, 0- and 0-50HZ. It will play a important role in your electronics work. Power Supply : built-in rechargeable battery, external -USB-5V, external power DC 15-30V, each way makes the generator work How to judge whether the module device is active or passive.Common methods : 1. Internal principle of the device, it is passive if "I+" is 24V+; it is active if "I-" is 24VG; 2. Use a multimeter to measure the voltag between "I+" and "I-", it is active if the vaule is 0V; it is passive if the vaule is 24V. Colour:Black Material:plastic Size:100x60x25mm Package Contents: 1*Signal Generator Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.