To design and build the digital circuit described above, you will need the following steps and components:
1. Start by understanding the requirements:
- The circuit should have three sensors at the finish line that send signals in the order the cars cross the finish line.
- The signals are 10ms HIGH pulses, one pulse per race.
- There is a 3x3 matrix of LED indicators that show the placement of each car.
- An R.S. flip-flop is used to light each LED.
- A two-bit binary counter will be incremented every time any track pulse occurs.
- Gating circuits are advised.
- A push button is used to reset the circuit and turn off all the LEDs.
2. Identify the necessary components:
- 3 monostable multivibrators (these will convert the 10ms pulses into stable signals).
- 9 RS flip-flops (one for each LED in the matrix).
- 1 7476 gating chip (to control the timing and sequencing of the LEDs).
3. Determine the circuit diagram:
- Connect each sensor to a separate monostable multivibrator to convert the pulse into a stable signal.
- Connect the output of each multivibrator to the inputs of the 7476 gating chip.
- Connect the output of the gating chip to the clock inputs of the RS flip-flops.
- Connect the outputs of the RS flip-flops to the corresponding LEDs in the matrix.
- Connect the push button to a reset circuit that resets the binary counter and all the flip-flops.
4. Implement the circuit on a breadboard or PCB:
- Gather the necessary components.
- Follow the circuit diagram to connect them together.
- Double-check the connections and ensure everything is properly wired.
- Test the circuit for functionality, making sure each LED lights up in the correct position based on the order of the cars crossing the finish line.
5. Once the circuit is working correctly, it can be transferred to a more permanent circuit board or integrated into a larger system if necessary.
Note: While we have provided a general guide for the design and components needed, it's important to consult the datasheets and documentation for each component and chip you intend to use for specific pin configurations and connection details.