Diode–transistor logic
（重定向自Diode transistor logic）
![](/Images/godic/202501/09/DTL_NAND_Gate.svg1420.png")
![A digital clock made only with discrete transistors, diodes and resistors, no integrated circuits. This clock uses 550 switching diodes and 196 transistors to divide 60 Hz power line frequency down to one pulse per second and provide a display of hours, minutes and seconds.](/Images/godic/202501/09/Transistor_Clock1420.jpg")
Diode–transistor logic (DTL) is a class of digital circuits that is the direct ancestor of transistor–transistor logic. It is called so because the logic gating function (e.g., AND) is performed by a diode network and the amplifying function is performed by a transistor (in contrast with RTL and TTL).