Stopwatch Timer Cascading 7 Segment Displays
Build of material:
- Two 7 segment displays
- Resistor packs (100 Ohms) *included in updated model
- Two 74ls190 (up/down counters)
- Two 74ls47 (BCD decoder)
- 555 Timer (1MHz digital clock in Multisim)
- One toggle switch (up/down)
- 1 Tact push button switch (reset)
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.