the control unit can maintain a constant output current characteristics. led voltage characteristics from the work point of view, menu board such control device is most appropriate, it does not require additional current limiting impedance, the output can be connected directly in the led load. led control output current control devices, if not a stable output current, the internal characteristics of a constant current circuit is not perfect, such as internal limiting use of inductance or capacitance of the circuit. such circuits from the output side to watch the outputimpedance, less than a constant current output control device,but significantly higher than the control output voltage control devices.
thus, in testing, according to iec 61000-3-2 standards, measuring instruments and electronic control devices should be required between the bandwidth increases with a 5khz low-pass filter or filtering function used with this digital power meter (such as led billboard yokogawa wt2010 and wt3000, etc.), so as to ensure reasonable power factor of the project and accuracy of detection. (for the terms of the detection principle and the detailed requirements.
at the same time designers no longer have the headache for theimpedance matching; 2.3, digital optical transmitter can be modulated drive circuit. digital baseband signal as long as the line through a simple code,led signboard you can directly drive optical transmitter. now, the price of fiber optic devices has dropped significantly compared with the previous, and future price increases as the cable and fiber optic devices further decline in prices, people will no longer select the first optical fiber, regardless of price.