Multisim| Stopwatch Timer Cascading 7 Segments 74ls190 74ls47

Stopwatch Timer Cascading 7 Segment Displays

Written by Larsha Johnson
12/19/2015

In this blog a stopwatch is simulated in Multisim and converted to a PCB layout via Ultiboard

Build of material:

1. Two 7 segment displays
2. Resistor packs (100 Ohms) *included in updated model
3. Two 74ls190 (up/down counters)
4. Two 74ls47 (BCD decoder)
5. 555 Timer (1MHz digital clock in Multisim)
6. One toggle switch (up/down)
7. 1 Tact push button switch (reset)

You will need:  7 segment - common anode   74ls190 - up/down counter 74ls47 - decoder/driver Switch Clock pulse - 555 timer or such 5V Power source

automatic_7_seg_counter.ms14 Download File Seven segments are everywhere, clocks, elevators, microwaves, cars, etc. To connect the 7 segments, match A-G segments to the pins of the decoder according to the datasheet. RI, BI, LT should be connected to VCC. The 74ls190 can be preset to a specific start time. ​ Seven segments and decoders are one of the most common types of parts I used to build circuits during my first years studying Computer Engineering Technology. Knowing the difference between anode and cathode use to be a task as well as knowing which type of decoder to use. Now that I have played around with them I am able to build more circuits using the two.

As a beginner you may want to try this 7 Segment Counter project. In the video you will see how I designed an up/down automatic counter and the list of parts I used.

Snippet for drag and drop coming soon.

*Visit our Git page for free files. https://github.com/Bits4Bots