Computing: Free Pascal Programming

Electronics: Simulation of IC-555-based timer circuits.


Download TimerCircuits555 desktop application (Windows 64bit) Download TimerCircuits555 source code (Lazarus/Free Pascal)

Description: TimerCircuits555 is a simple electronics application that simulates bistable, monostable and astable circuits implemented with a 555 timer IC (e.g. NE555). Users may choose to calculate the time period (monostable) or the mark and the space time (astable) for given resistances, or to calculate the resistances needed to get given time period values. Pushing the switches (bistable and monostable) resp. starting the simulation (astable), they can observe in real time, what happens at the circuit's output (LEDs going on or out).
Users can select if the output is one or two LEDs and how they are connected ("source" or "sink"). The bistable circuit can be implemented by using the Reset or the Threshold pin of the 555; the monostable circuit can include or not a supplementary reset switch; the astable circuit can include or not a diode in parallel with R2 (allowing or not to get duty cycles less than 50%). Application help included as HTML file.

Free Pascal features: Usage of timers. Using shapes to create a specific layout. Using transparent images as mouse-click-areas. Modification of the brush style during run-time to simulate real time events.

Screenshots:

IC-555 timer circuits simulation: Monostable circuit
 
IC-555 timer circuits simulation: Astable circuit