The main function of this chip is to act as a monostable timer. A monostable timer is a timer that once activated sets an output high for a specified period of time, then stops waiting to be told to start again. If you are not up to speed on the , have a look at my extensive review. It is also available in various surface-mount options.
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The main function of this chip is to act as a monostable timer. A monostable timer is a timer that once activated sets an output high for a specified period of time, then stops waiting to be told to start again.
If you are not up to speed on the , have a look at my extensive review. It is also available in various surface-mount options. Note that this is a CMOS semiconductor, and that you should practice good anti-static precautions when handling it. Here is the data sheet from ON Semiconductor. That is: , , and With wiring you select which value to count to, and also the action to take whilst counting and once finished.
The following table from the data sheet details this: And here are the pinouts: The speed of the counting the frequency is determined by a simple RC circuit. For more information on RC circuits, please visit this post. You can calculate the frequency using the following formula: There are two external resistors used in the circuit — Rtc and Rs.
Rs needs to be as close as possible to twice the value of Rtc. Also remember to take note of the restrictions printed next to the formula above. Before examining a demonstration circuit, I would like to show you how to calculate your timing duration. As you can see from the formula above, calculating the frequency is easy enough.
Once you have a value for f, the number of counts per second divide this into the count value less one power you have wired the chip. Remember to convert your values back to base units. So resistance in ohms, and capacitance in farads. To make these calculations easier, there is a spreadsheet you can download here.
For example: Here is my demonstration monstable circuit. Once the power has been turned on the counter starts, and once finished the LED is lit. Or if the circuit already has power, the reset button SW1 is pressed to start counting.
And my demonstration laid out I really do make everything I write about : Easily done. Although this IC has been around for a long time, and many other products have superseded it, the can still be quite useful.
For example, an Arduino system might need to trigger a motor, light, or something to runfor a period of time whilst doing something else. Unfortunately thankfully? Arduino cannot multi-task sketches, so this is where the can be useful.
You only need to use a digitalWrite to send a pulse to pin 6 of your timer circuit, and then the sketch can carry on, while the timer does its job and turns something on or off for a specified period of time. Well I hope you found this part review interesting, and helped you think of something new to make. As always, thank you for reading and I look forward to your comments and so on.
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