1 / 13

The 555 Timer

The 555 Timer. What is a 555 timer?. The 555 timer is one of the most remarkable integrated circuits ever developed. It comes in a single or dual package and even low power CMOS versions exist

rasia
Télécharger la présentation

The 555 Timer

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The 555 Timer

  2. What is a 555 timer? • The 555 timer is one of the most remarkable integrated circuits ever developed. It comes in a single or dual package and even low power CMOS versions exist • The 555 timer consists of two voltage comparators, a bi-stable flip flop, a discharge transistor, and a resistor divider network.

  3. Applications for 555 timer • The 555 timer can be used in many ways and is very versatile. • Common uses are for precision timing, pulse generation, sequential timing, time delay generation and pulse width modulation (PWM). –(ie.motor speed control)

  4. Pin Configuration Pin1: ground Pin2: trigger input to lower comparator Pin3: output high ( 200mA max) Pin4: reset latch to low state

  5. Pin Configuration Pin5:gives access to voltage divider Pin6: input to upper comparator Pin7: an open collector to discharge Pin8: power source

  6. Astable Acts as a timer Pulses at precise intervals. Most popular Monostable(one-shot) Outputs only a single pulse Two operations

  7. 555 timer Wiring 1st step is to connect pins 2 and 6 together.Then give power to pins 4,and 8 and ground pin 1.

  8. 2nd part • 3 components are needed to make 555 timer work. • 2 resistors(R1,R2), and a capacitor(C1). These components determine how fast the timer will work in hertz. The equation to figure out what hertz they will run at is: 1.44 / ((R1 + (2 * R2) * C)

  9. Resistors • R1 goes between pins 8 and 7, so we'll put a 1,000 ohm resistor there. R2 goes between pins 7 and 6, so we'll put a 5,000 ohm resistor there.

  10. Capacitor • Now it's time to add the capacitor. It goes between pins 6(threshold) and pin 1 (ground). Now this circuit is ready to be used!

  11. Output to LED • The output of the timer is pin3 so now its time to connect an LED with a wire, then connect a resistor from the negative end of the LED to ground for protection.

  12. What is my frequency?? • If I used a 1,000ohm resistor for R1, and a 5,000 ohm resistor for R2, and a 130 microfarad capacitor(0.00013 F), at what hertz is my LED going to be flashing? 1.44 / ((1000 + 2 * 5000) * 0.00013)= 1.44 / ((1000 + 10,000) * 0.00013)= 1.44 / (11,000 * 0.00013)= 1.44 / 1.43= 1 (Approximately)

  13. Overview • 555 timer is very versatile. • Consists of two voltage comparators, a bi-stable flip flop, a discharge transistor, and a resistor divider network. • Can be wired as Astable or monostable multivibrators. • Astable most popular (timing)

More Related