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Shift Register

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The Shift Register

On the rising edge of the clock pulse, each D is copied to the next Q and all the data moves one place to the right.
The data moves one place to the right along the shift register like suitcases on a conveyor belt.
Pulses can be delayed using this circuit.
Shift registers can be used in simple combination locks. The registers have to be clocked in the correct sequence to unlock the door.

For the Falstad Circuit Simulation, CTRL+Click Shift Register
In options, check European Resistors and uncheck Conventional Current.
Toggle the switch to feed pulses into the input.

Alternatively view Shift_Register.txt.
Save or copy the text on the web page. Import the saved or copied text into the Falstad simulator.

Here is the new HTML5 Simulator Site.

Pseudo-Random Number Generator

For the Falstad Circuit Simulation, CTRL+Click Random Number Falstad Simulation
In options, check European Resistors and uncheck Conventional Current.

Alternatively view Random_Number.txt.
Save or copy the text on the web page. Import the saved or copied text into the Falstad simulator.

Here is the new HTML5 Simulator Site.

Notice the diagonal pattern in the truth table.
Each row is copied and shifted one place to the right.
All shift registers work like this.

D Type Flip Flop Pseudo Random Number Generator

A2 - Serial to Parallel Conversion

The shift register can be used to delay pulses.

It can also be used to collect a serial stream of pulses. Once all the bits (usually eight) have been collected (a byte) the stored data can be copied to an eight bit latch (a parallel device).

The data is clocked in one bit at a time. When all eight bits have been clocked in, the Parallel data is available at the output.

D Type Flip Flop Shift Register SP.gif

Parallel to Serial Conversion

First reset all the flip flops. This clears any old data.
Now each input line is used to set each flip flop.
An input line carrying a zero will not clear the flip flop. This is why the first reset step is required.
Finally clock the shift register. Each bit comes out of the last flip flop.
On the rising edge of each clock pulse, the next bit of data arrives at the output.

D Type Flip Flop Shift Register PS.gif

For the Falstad Circuit Simulation, CTRL+Click Parallel to Serial Converter
In options, check European Resistors and uncheck Conventional Current.
Follow the Three Steps

Alternatively view Serial_To_Parallel.txt.
Save or copy the text on the web page. Import the saved or copied text into the Falstad simulator.

Here is the new HTML5 Simulator Site.