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Welcome to my LM555 Timer Calculator program.

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There are only a few things to know about using it.

1. You can caluculate the frequency by entering the values for the two resistors and the capacitor then clicking the 'Calc Freq' button.
2. You can calculate the capacitor value by entering the two resistor values and the frequency then clicking the 'Calc C' button.
3. Finally, you can calculate the resistors by entering the frequency, the desired duty cycle, and the capacitor value then clicking the 'Calc R's' button. NOTE: if you leave out the desired duty cycle the program will try to find the answer with a duty cycle of 50.1%.

The input resistor and capacitor scaling values (KOhms, MegaOhms, etc.) are selected by dropdowns. The input freqency and period scaling are done by double clicking the appropriate value ("Hz", "KHz", etc.).

The appropriate scale factor for the answer will be selected by the program when you do a calculation.

The LM555 can only go about as high as 1 MHz and if you select or calculate a frequency value larger than 500 KHz the frequency box will turn colors from yellow to red depending on how high the frequency is.