This will overwrite any earlier breadboard of this schematic. Are you sure?
Use the following steps to complete the wiring of the breadboard
- Select your circuit. If this is your first time, choose the SR NAND or SR NOR.
- Operate the switches in the circuit simulator. Read the description of the circuit if you need additional information.
- Using the schematic, wire up the circuit in the breadboard simulator. When a wire end is placed in a socket of the breadboard that corresponds to a node on the schematic, the respective node of the schematic will turn red.
- If a correct connection is made, the wire ends will snap into the socket.
- Note that all the VCC (red wire) and GND (black wire) connections are already done.
- When all the nodes are wired up, a red LED will light up near the VCC/GND terminals.
- You may now operate the breadboard switches and observe the LED results.
- When you wire up the circuit using a real digital trainer, do remember to wire the VCC and GND wires and power up the digital trainer.
- You must login using your facebook account to save or restore the breadboard connections.
- Click to close any of the panes (breadboard/schematic/description/help) and click on the corresponding menu item to open it.
If you are unfamiliar with the breadboard, there are many resources available online that explains how to they work.
- Breadboard Tutorial from EECE 213L: Circuits II Lab Course.
A Johnson counter is a modified ring counter, where the inverted output from the last flip flop is connected to the input to the first. The register cycles through a sequence of bit-patterns. The MOD of the Johnson counter is 2n if n flip-flops are used. The main advantage of the Johnson counter counter is that it only needs half the number of flip-flops compared to the standard ring counter for the same MOD.
This circuit is implemented using D-type flip-flops.
- Enable the flips flops by clicking on the RESET switch (SW6).
- Click on CLK (SW7) switch and observe the changes in the outputs of the flip flops. SW7 is a momentary switch.
- The D flip flop clock has a rising edge CLK input. For example Q1 behaves as follows:
- The D input value just before the CLK rising edge is noted (Q0).
- When CLK rising edge occurs, Q1 is assigned the previously noted D value (Q0).
- The MOD or number of unique states of this 3 flip flop johnson counter is 6.