Active pixel circuit, image sensor, and electronic device

An active pixel circuit comprising a photodiode and at least three MOS transistors, the at least three MOS transistors comprising at least one first MOS transistor, at least one second MOS transistor, and at least one third MOS transistor,

• wherein the at least one first MOS transistor serves as a transfer transistor, the transfer transistor connected to both the photodiode and a corresponding third MOS transistor and configured to transmit a photoelectric signal from the photodiode,
• wherein the at least one third MOS transistors serving as a reset transistor, the reset transistor connected to a terminal of a respective one of the transfer transistor(s) for outputting the photoelectric signal and configured to reset the active pixel circuit,
• wherein each transfer transistor has a higher threshold voltage than each third MOS transistor, and each transfer transistor has a smaller off-state leakage current under operating voltage than each third MOS transistor,
• the active pixel circuit employs a correlated double sampling technique,
• wherein a threshold voltage of each reset transistor is higher than a threshold voltage of each third MOS transistor and an off-state leakage current under operating voltage of each reset transistor is smaller than an off-state leakage current under operating voltage of each third MOS transistor, or a threshold voltage of each reset transistor is lower than a threshold voltage of each transfer transistor and an off-state leakage current under operating voltage of each reset transistor is greater than an off-state leakage current under operating voltage of each transfer transistor.