Tool and Library Reference

Toolbar for quick access. Use these to edit or interact with your circuit, or to add your favorite components.
Right-click or drag items to customize toolbar for each project.

Circuit List for your project. Double-click to open a circuit. Or, single-click to place one as a sub-circuit within another.
A circuit can be embedded as a sub-circuit within another, by selecting with single-click, then clicking to place it.

Standard and Custom Libraries of components to build your circuits. Click to select, then click to place in your circuit.
Tip: Go to Project > Load Library to add more libraries.

Properties to configure tools and components in the circuit. Also try the quick help panel for reference.

Mouse Tools

The toolbar includes most mouse tools by default. All are also visible in Project > Options when customizing the toolbar, or in mouse options when creating custom keyboard shortcuts.

Component Libraries

Logisim comes with the following built-in components, visible in the left sidebar of each project. These can also appear in the toolbar. You can add additional libraries to your project using Project > Load Library, including third-party libraries found online, and you can even write your own custom jar library or use import one project file into another to be used as a custom .circ library.

Wiring library — Basic elements needed for most circuits
	Split/Join Signals — join signals into buses, or split busses into separate signals
	Input & Output Pin — input to and output from a circuit
	Probe — display values on wires
	Tunnel — make connections without drawing wires
	Clock — oscillates between zero and one
	Constant — like an input, but with a fixed value
	Extend/Truncate — zero-extend, sign-extend, or truncate a value
Gates Library — Primitive combinational components
	NOT Gate — inverts a signal
	Buffer — does nothing, no-op
	AND, OR, NAND, NOR, XOR, XNOR Gates — common logic operations
	Odd Parity, Even Parity — parity operations
	Tri-state Buffer, Tri-state Inverter — gates with three possible outputs
	PLA — Programmable Logic Array
Plexers Library — controlling and selecting groups of signals
	Multiplexer — select one value from of a group of wires
	Demultiplexer — send a value to one of a group of wires
	Decoder — enable one out of a group of wires
	Priority Encoder — check which wire among a group is enabled
	Bit Selector — select one bit from a bus
Arithmetic Library — computing with binary numbers
	Adder — add binary numbers
	Subtractor — subtract binary numbers
	Multiplier — multiply binary numbers
	Divider — divide binary numbers
	Negator — negate two's complement binary numbers
	Comparator — compare binary numbers
	Shifter — shift binary patterns left or right
	Bit Adder — count the enabled bits in a bus value
	Bit Finder — search for a bit in a bus value
Memory Library — storing data
	D, T, J-K, S-R Flip-Flops — store a single-bit
	Register — store multiple bits
	Counter — store, increment, and decrement a number
	Shift Register — store and shift a bit pattern
	Random Generator — generate random numbers
	RAM — random-access memory
	ROM — read-only memory
Input/Output Library — user interaction
	Button — a push-button for user input
	DIP Switch — a row of small switches for user input
	LED — single-bit output as a colored light
	LED Bar — a row of LEDs for displaying multi-bit values
	RGBLED — three-bit output as a multi-colored light
	7-Segment Display — display numbers or patterns
	Hex Digit Display — display 4-bit data as a hex digit
	Meter — displays a value on a analog-style meter or dial gauge
	Slider — user input using a linear or log-scale slider
	Dial — user input using a linear or log-scale dial
	Dial — output to an oscilloscope-style display
	Joystick — arcade-style joystick for x,y user input
	Keyboard — ascii text user input
	TTY — display ascii text
	Port I/O — bi-directional input/output (useful for FPGAs)
	File Viewer — display lines from a file
	Slideshow — chooses and displays an image depending on a control signal
	LED Matrix — a grid of 1-bit lights
	RGB Video — full-color video output
Analog Library — simplistic non-digital components
	Power, Ground — signal source and sink
	Transistor — simplified PNP and NPN transistors
	Transmission Gate — block or transmit a signal
	Pull Resistor — weakly pull signal to a default value
Audio Library — digital audio
	Octave — a simulated piano keyboard for generating audio
	PCM Sink — converts circuit-generated PCM data to audio output
	MIDI Sink — converts circuit-generated MIDI data to audio output
	MIDI Input — connects an external source of MIDI data to a Logisim circuit
	Saturating Adder — addition using scaled, saturating, or normalized arithmetic
	Saturating Subtraction — subtraction using scaled, saturating, or normalized arithmetic
	Saturating Negator — negation using scaled, saturating, or normalized arithmetic
	Saturating Multiplier — multiplication using scaled, saturating, or normalized arithmetic
	Saturating Divider — division using scaled, saturating, or normalized arithmetic
	Requantizer — scale and normalize values
	Linear Map — shift values between preset ranges
	Scaled Math & Trig — evaluate mathematicaal and trigonometric expressions with scaled arithmetic
	Line Select — select or mix values from among multiple inputs
BFH mega functions — miscellaneous advanced components
	Dynamic Clock Control — control FPGA clock speed dynamically
	Timed Pulse — generate pulses at a known, fixed rate
	Bin2BCD — binary to binary-coded-decimal conveter
	BCD2SevenSegment — 4-bit binary-coded-decimal to seven-segment adapter
	Hex2SevenSegment — 4-bit hex to seven-segment adapter
External I/O — a portal to the world outside the simulation
	Serial Input — get realtime data from USB and other serial devices
	Http Input — get realtime data from the web
	Real Time Clock — get realtime time and date data
Decor Library — decorative elements
	Plain & Styled Comment — add text blocks to comment a circuit
	Callout Tool — add callouts for highlighting specific features of a circuit
	Image Tool — add images to document your circuit
	Hyperlink — add a button linking to a web page

Wiring library — Basic elements needed for most circuits

Split/Join Signals — join signals into buses, or split busses into separate signals

Input & Output Pin — input to and output from a circuit

Probe — display values on wires

Tunnel — make connections without drawing wires

Clock — oscillates between zero and one

Constant — like an input, but with a fixed value

Extend/Truncate — zero-extend, sign-extend, or truncate a value

Gates Library — Primitive combinational components

NOT Gate — inverts a signal

Buffer — does nothing, no-op

AND, OR, NAND, NOR, XOR, XNOR Gates — common logic operations

Odd Parity, Even Parity — parity operations

Tri-state Buffer, Tri-state Inverter — gates with three possible outputs

PLA — Programmable Logic Array

Plexers Library — controlling and selecting groups of signals

Multiplexer — select one value from of a group of wires

Demultiplexer — send a value to one of a group of wires

Decoder — enable one out of a group of wires

Priority Encoder — check which wire among a group is enabled

Bit Selector — select one bit from a bus

Arithmetic Library — computing with binary numbers

Adder — add binary numbers

Subtractor — subtract binary numbers

Multiplier — multiply binary numbers

Divider — divide binary numbers

Negator — negate two's complement binary numbers

Comparator — compare binary numbers

Shifter — shift binary patterns left or right

Bit Adder — count the enabled bits in a bus value

Bit Finder — search for a bit in a bus value

Memory Library — storing data

D, T, J-K, S-R Flip-Flops — store a single-bit

Counter — store, increment, and decrement a number

Shift Register — store and shift a bit pattern

Random Generator — generate random numbers

RAM — random-access memory

ROM — read-only memory

Input/Output Library — user interaction

Button — a push-button for user input

DIP Switch — a row of small switches for user input

LED — single-bit output as a colored light

LED Bar — a row of LEDs for displaying multi-bit values

RGBLED — three-bit output as a multi-colored light

7-Segment Display — display numbers or patterns

Hex Digit Display — display 4-bit data as a hex digit

Meter — displays a value on a analog-style meter or dial gauge

Slider — user input using a linear or log-scale slider

Dial — user input using a linear or log-scale dial

Dial — output to an oscilloscope-style display

Joystick — arcade-style joystick for x,y user input

Keyboard — ascii text user input

TTY — display ascii text

Port I/O — bi-directional input/output (useful for FPGAs)

File Viewer — display lines from a file

Slideshow — chooses and displays an image depending on a control signal

LED Matrix — a grid of 1-bit lights

RGB Video — full-color video output

Analog Library — simplistic non-digital components

Power, Ground — signal source and sink

Transistor — simplified PNP and NPN transistors

Transmission Gate — block or transmit a signal

Pull Resistor — weakly pull signal to a default value

Audio Library — digital audio

Octave — a simulated piano keyboard for generating audio

PCM Sink — converts circuit-generated PCM data to audio output

MIDI Sink — converts circuit-generated MIDI data to audio output

MIDI Input — connects an external source of MIDI data to a Logisim circuit

Saturating Adder — addition using scaled, saturating, or normalized arithmetic

Saturating Subtraction — subtraction using scaled, saturating, or normalized arithmetic

Saturating Negator — negation using scaled, saturating, or normalized arithmetic

Saturating Multiplier — multiplication using scaled, saturating, or normalized arithmetic

Saturating Divider — division using scaled, saturating, or normalized arithmetic

Requantizer — scale and normalize values

Linear Map — shift values between preset ranges

Scaled Math & Trig — evaluate mathematicaal and trigonometric expressions with scaled arithmetic

Line Select — select or mix values from among multiple inputs

BFH mega functions — miscellaneous advanced components

Dynamic Clock Control — control FPGA clock speed dynamically

Timed Pulse — generate pulses at a known, fixed rate

Bin2BCD — binary to binary-coded-decimal conveter

BCD2SevenSegment — 4-bit binary-coded-decimal to seven-segment adapter

Hex2SevenSegment — 4-bit hex to seven-segment adapter

External I/O — a portal to the world outside the simulation

Serial Input — get realtime data from USB and other serial devices

Http Input — get realtime data from the web

Real Time Clock — get realtime time and date data

Decor Library — decorative elements

Plain & Styled Comment — add text blocks to comment a circuit

Callout Tool — add callouts for highlighting specific features of a circuit

Image Tool — add images to document your circuit

Hyperlink — add a button linking to a web page

	Poke Tool — interact with running simulation
	Edit Tool — select and move components, or draw and edit wires
	Wiring Tool — draw and edit wires only
	Wire Cutter — delete wires or cut portions of wires
	Text Tool — add text boxes, or edit labels on components
	Move Tool— move and select components only
	Popup Menu Tool — bring up the right-click context menu, as an alternative to right-clicking