The 74HC393; 7474HCT393 is a dual 4-stage binary ripple counter. Each counter features a clock input (nCP), an overriding asynchronous master reset input (nMR) and 4 buffered parallel outputs (nQ0 to nQ3). The counter advances on the HIGH-to-LOW transition of nCP. A HIGH on nMR clears the counter stages and forces the outputs LOW, independent of the state of nCP. Inputs include clamp diodes. This enables the use of current limiting resistors to interface inputs to voltages in excess of VCC.

Main Content


A digital quartz clock from scratch

“After 20+ years of programming, I wanted to get some understanding of the electronics that make my career possible. I had built the basic individual logic gates with transistors on a breadboard, but to build anything meaningful I needed loads …

74HC393 Binary Counter

“The 74HC393 is a widely used ic chip. Its main function is as a binary counter. A binary counter is similar to a Decade counter such as the well known 4017 Johnson counter, but the 74HC393 counter functions slightly differently …

Driving a Stepper Motor Without a Microcontroller.

“In this Instructable, I will drive a 28-BYJ-48 step motor, with a UNL2003 darlington array board, sometimes named x113647, without a micro controller. It will have start/stop, forward/backward, and speed control. The motor is a uni-polar …