One time Pulse with a 555 Timer

• scottietohottie
In summary, Scott wants to create a circuit that will generate a single pulse output with a variable width. He has replaced the resistor with a potentiometer to make the output variable, but is having difficulty getting the circuit to work. He needs to start with debouncing his switch and then convert the constant input to a single pulse.
scottietohottie
Hello

I currerntly have this circuit -

https://www.physicsforums.com/attachment.php?attachmentid=8419&stc=1&d=1164497449
circuit1.jpg

I am trying to keep it as simple as possible. I have scoured loads of site etc, an have even found the circuit I want, or should I say it is described as the one I want.

I have replaced R with a potentiometer to make the output variable, but the aim is to make this a one time circuit. I want to push a current through the circuit it fire for a variable amount of time (via the potentiometer), then stop even though the trigger has not.

I have been told that this is done with the use of and extra capacitor, resistor, LED and Transistor (used as a not gate) to get this to work. So far all of the layouts I have been given have not worked. Any ideas would be great.

Thanks
Scott

Attachments

• circuit1.jpg
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So I am guessing that the answer is is harder than I thought. Darn. Any ideas what could produce a similar action?

Sorry, what exactly is the function that you want to generate? When you push a button, you want a single pulse output, where the width of the pulse is variable with a potentiometer? Is it at each button push, or is there a reset or something needed to get ready for the next fire? You'll need to start with debouncing your switch, of course. Do you know how to do that? What is the range of output pulse widths you want to generate? To what accuracy?

Sorry took so long (Computer crashes are gay hum k). I have a constant input and I want to convert it to a single pulse, the length is between 0.25 secs to 10 sec or near as can be. A switch is thrown that gives a constant input which will trigger the circuit to give an output of the same power (12 car battery) for T (where T is time between 0.25 and 10 secs). Had so much fun tring to get the answer to this question.

What is a 555 Timer and how does it work?

A 555 Timer is a popular integrated circuit used in electronic circuits to generate precise and stable timing pulses. It consists of a comparator, a flip-flop, and a discharge transistor. When triggered, the 555 Timer produces a high output for a set amount of time before returning to its low state.

What is a one time pulse and how is it created with a 555 Timer?

A one time pulse, also known as a monostable pulse, is a single output pulse that is triggered by an external signal. This pulse is generated by configuring the 555 Timer in its monostable mode, where the output remains low until a trigger signal is received. Once triggered, the 555 Timer produces a high output for a predetermined amount of time before returning to its low state.

What is the purpose of using a one time pulse with a 555 Timer?

A one time pulse with a 555 Timer is commonly used in electronic circuits to control the timing and duration of various actions. It can be used in applications such as blinking LEDs, controlling motors, and generating precise delays. The one time pulse ensures that the circuit performs a specific action only once in response to a trigger signal.

How can the duration of a one time pulse be adjusted with a 555 Timer?

The duration of a one time pulse can be adjusted by changing the values of the external resistors and capacitors connected to the 555 Timer. The formula for calculating the duration of the pulse is t = 1.1 x R x C, where t is the pulse duration in seconds, R is the resistance in ohms, and C is the capacitance in farads. By adjusting these components, the pulse duration can be increased or decreased as needed.

What are the advantages and limitations of using a 555 Timer to generate a one time pulse?

The 555 Timer is a versatile and reliable integrated circuit that is readily available and easy to use. It has a wide range of applications and can generate precise timing pulses. However, it is limited in its ability to generate very short pulses and may have slight variations in its timing accuracy. Additionally, the output of the 555 Timer may be affected by external noise or other interfering signals.

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