Up down counter using 8051 microcontroller (AT89C51)
This article shows an easy to build up down counter. The counter is based around the 8051 microcontroller (AT89C51). Two switches are provided, one for increment and second for decrement. The switches can also be replaced by sensors to increment or decrement.
In this circuit, four seven segment display are used to show the value of count. The maximum value of count is 9999. The circuit uses the concept of multiplexing of seven segment to display the value of count. For more details on seven segment multiplexing, refer article titled “Seven segment multiplexing”.
BC547 is an NPN bi-polar junction transistor. A transistor, stands for transfer of resistance, is commonly used to amplify current. A small current at its base controls a larger current...
Seven Segment Display
A seven segment display is the most basic electronic display device that can display digits from 0-9. They find wide application in devices that display numeric information like digital clocks, radio, microwave ovens...