Library: Wiring
Introduced: 2.0 Beta 13 (in Base library, moved to Wiring in 2.7.0)


The clock toggles its output value on a regular schedule as long as ticks are enabled via the Simulate menu. (Ticks are disabled by default.) A "tick" is Logisim's unit of time; the speed at which ticks occur can be selected from the Simulate menu's Tick Frequency submenu.

The clock's cycle can be configured using its High Duration and Low Duration attributes.

Note that Logisim's simulation of clocks is quite unrealistic: In real circuits, multiple clocks will drift from one another and will never move in lockstep. But in Logisim, all clocks experience ticks at the same rate.


A clock has only one pin, an output with a bit width of 1, whose value will represent the current value of the clock. The location of this pin is specified in the Facing attribute. The clock's value will toggle on its schedule whenever ticks are enabled, and it will toggle whenever it is clicked using the Poke Tool.


When the component is selected or being added, the arrow keys alter its Facing attribute.

The side of the component where its output pin should be.
High Duration
The length of time within each cycle that the clock's output should be 1.
Low Duration
The length of time within each cycle that the clock's output should be 0.
The text within the label associated with the clock component.
Label Location
The location of the label relative to the component.
Label Font
The font with which to render the label.

Poke Tool Behavior

Clicking a clock component will toggle its current output value immediately.

Text Tool Behavior

Allows the label associated with the component to be edited.

Back to Library Reference