GOA circuit and method for driving the same and LCD

A liquid crystal display (LCD) comprising a gate on array (GOA) circuit, the GOA circuit comprising:

• a plurality of GOA units connected in cascade, an Nth GOA unit comprising an Nth stage-transmittance circuit, an Nth Q-node controlling circuit, an Nth P-node controlling circuit, an Nth outputting circuit, and a first switch circuit where N is a positive integer;
• wherein the Nth stage-transmittance circuit is connected to the Nth Q-node controlling circuit, the Nth Q-node controlling circuit is connected to the Nth outputting circuit via a Q node, the Nth stage-transmittance circuit is connected to the Nth P-node controlling circuit, the Nth P-node controlling circuit is connected to the Nth outputting circuit via a P node, and further, the Nth outputting circuit is connected to the Nth scanning line;
• the first switch circuit connected to the Nth scanning line, for inputting an enabling signal to the Nth scanning line before the LCD shows images so as to turn on a thin-film transistor (TFT) in a pixel which the Nth scanning line is connected to,
• wherein the Nth Q-node controlling circuit comprises:
• a seventh TFT, a gate of the seventh TFT receiving an (N−2)th clock signal, a drain of the seventh TFT receiving an (N−2)th scanning signal in a period of forward scanning or receiving an (N+2)th scanning signal in a period of reverse scanning, and a source of the seventh TFT connected to the Q node;
• an eighth TFT, a gate of the eighth TFT receiving an (N−2)th scanning signal G(N−2), a drain of the eighth TFT connected to the P node, and a source of the eighth TFT receiving a signal at low level;
• a ninth TFT, a gate of the ninth TFT connected to the drain of the eighth TFT, a drain of the ninth TFT connected to the source of the seventh TFT, and a source of the ninth TFT connected to a signal at low level.