digital camera a personal digital assistant pda a notebook computer a desktop computer a television a global positioning system gps a car media player an avionics display a digital photo frame a portable video player etc in this embodiment the electronic device 10 includes an amoled display 20 and a controller 25 the amoled display 20 has a panel 21 and the panel 21 has an active area aa 22 a pixel array 23 in active area 22 has a plurality of data lines and scan lines the controller 25 controls the operation of pixel driving circuits of the pixel array 23 to present images on the display 20 as shown in fig3 a the pixel driving circuit 300 a includes a storage capacitor cst a first switching circuit 310 a second switching circuit 320 a third switching circuit 330 and a driving element 305 the first switching circuit 310 is disposed between the first node a of the capacitor cst and a fixed voltage source vdd of the panel 21 note that the fixed voltage source vdd can output a voltage around 5v for example however the actual voltage received by a pixel from the fixed voltage source vdd would depend on the.