Questions tagged [555]

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation and oscillator applications. The part is still in widespread use, thanks to its ease of use, low price and good stability. The 556 timer is simply two 555 timers in a single package.

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How do I pick a part that goes into a breadboard when I order it?

I have just bought some 555 timers and they are timers for microelectronic circuits...could anyone tell me what I need to search for in order to get larger ones which will fit a breadboard? Thanks
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1answer
2k views

Losses in NE555 oscillator and Sallen-Key filter

I use a Sallen-Key bandpass filter in a project at university to isolate the 1kHz sinusoidal part of a square signal produced by a NE555 oscillator. Here is my circuit: When I simulate it on PSpice, ...
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1answer
104 views

LM555CN chip acting weird

I'm in high school computer engineering, and I'm experimenting with the 555 Timer chip on my own. I'm using the Electronic Experimenter Box. Pin 8 is connected to +5V Pin 1 connected to ground LED1 ...
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2answers
638 views

Where is the oscilator in the 555 chip provided here?

I have tried a while to understand how the 555 chip is built, I opened the datasheet of TI available here : http://www.ti.com/lit/ds/symlink/lm555.pdf anyway this is the scematic from the datasheet ...
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3answers
10k views

What are the disadvantages of using a 555 timer as a resistance to frequency converter?

Since we know that a 555 timer configured as an astable multivibrator depends on the resistance the timing capacitor sees, what stops people from using a 555 as an ohmmeter? How does the accuracy ...
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4answers
631 views

Buzzer alarm problem

I've got an assignment to make some kind of alarm. When user presses the push button, 1kHz sound should be generated and outputted on some kind of speaker (I'll use buzzer). That part I know how to ...
2
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1answer
4k views

Ultrasonic signal generation

I am busy with a robotic arduino project. I have a 40kHz ultrasonic transducer and receiver. What would be the best way to generate the 40kHz signal to drive the transducer. I have found two ways to ...
5
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4answers
8k views

How can I make a 15 minute egg timer circuit?

I want to make a 15 minute timer for a game. I would like it to count down 3 x 5 minute segments of time, and then ring a bell when the 15 minutes is up. To do this, I want to push a button to ...
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2answers
4k views

Why are 555 IC pin diagrams so random?

I was going to start learning how to use a 555 timer as an oscillator, however am greatly confused in the pin configurations example schematics provide me. To show visually what I mean, A random ...
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6answers
4k views

6 Month Countdown Timer Circuit

I need to design a timing circuit. After a duration of 6 months a LED must come on. The LED can then be turned off at the press of a button and the 6 month count-down must begin again. Anyone have ...
9
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2answers
723 views

Why doesn't this radio transmitter correctly transmit some songs?

I made transmitter from this question with some minor modifications (100 K pot for resistor between 8 and 7 and 22K for resistor between 7 and 6. 22 pF for the capacitor). Here's the picture: When ...
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2answers
8k views

How do I drive a stepper motor using an LM555 timer?

I'm trying to drive a stepper motor's driver (QuadStepper) with an LM555 timer circuit, however the logic levels are known to be 5v compatible. While the driver has both 3.3 and 5 volt compatibility, ...
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1answer
2k views

555 timer as Dual Direction H-bridge driver

I am trying to design an analog direction driver circuit for an H-bridge configuration on a small DC motor. I have a pretty tight space constraint, and a simple requirement for my design, hence why I ...
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1answer
2k views

LED flashlight project: Need transistor ideas

This question is continuation of this question. I did some research on previous question and made a circuit as a starting point. Here's a picture: Now my problem is that TS555 device I plan to use ...
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2answers
596 views

Power cycling circuit

I am designing a circuit which may fail to start up. It has a power good output which is high when the supply is working. When the power good output goes low, the circuit has failed to start ...
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1answer
431 views

What's wrong with giving a really long low pulse to a 555 timer?

A number > 0 of 555 timer tutorials warn against holding the trigger of a 555 timer in monostable configuration low for longer than the duration of the output pulse. Why not?