Uporabniški priročnik za časovnik Jameco 555

Pin 1 (ozemljitev) priključite na ozemljitev vezja.
Apply a low-voltage pulse to Pin 2 (Trigger) to make the output (Pin 3) go high.
Use resistor R1 and capacitor C1 to determine the output duration.

Calculate R1 value using R1 = T * 1.1 * C1, where T is the desired timing interval.
Za natančno merjenje časa se izogibajte uporabi elektrolitskih kondenzatorjev.
Use resistor values between 1K ohms and 1M ohms for standard 555 timers.

Pin 1 (ozemljitev) priključite na ozemljitev vezja.
Capacitor C1 charges through resistors R1 and R2 in astable mode.
Izhodna napetost je visoka, medtem ko se kondenzator polni.
Izhod se zniža, ko je glasnosttage čez C1 doseže 2/3 dobavljenega volumnatage.

Izhodna moč se spet poveča, ko se glasnosttage na C1 pade pod 1/3 dobavljenega volumnatage.
Grounding Pin 4 (Reset) stops the oscillator and sets the output to low.

Kako konfigurirati časovnik 555 IC

555 Vadnica za časovnik
By Philip Kane
The 555 timer was introduced over 40 years ago. Due to its relative simplicity, ease of use and low cost it has been used in literally thousands of applications and is still widely available. Here we describe how to configure a standard 555 IC to perform two of its most common functions – as a timer in monostable mode and as a square wave oscillator in astable mode.

555 Timer Tutorial Bundle Includes

555 Signals and Pinout (8-pin DIP)

Figure 1 shows the input and output signals of the 555 timer as they are arranged around a standard 8 pin dual-in-line package (DIP).

Pin 1 – Ozemljitev (GND) Ta pin je priključen na ozemljitev vezja.
Pin 2 – Sprožilec (TRI) Nizka glasnosttage (manj kot 1/3 dobavljenega volumnatage) če se začasno uporabi na vhodu Trigger, se izhod (pin 3) dvigne na visoko raven. Izhod bo ostal visok, dokler se ne pojavi visoka glasnost.tage se uporabi na vhodu Threshold (pin 6).

Pin 3 – Output (OUT) In the output low state the voltage will be close to 0V. In the output high state the voltage bo 1.7 V nižji od napajalne napetostitage. Na primerampnpr., če je obseg dobavetage je 5V izhod z visoko napetostjotage bo 3.3 volta. Izhod lahko oddaja ali ponira do 200 mA (največ je odvisno od napetosti napajanja).tagin).

Pin 4 – Reset (RES) A low voltagČe na pin za ponastavitev pride napetost e (manj kot 0.7 V), bo izhod (pin 3) padel na nizko raven. Ta vhod mora ostati priključen na Vcc, ko ni v uporabi.

Pin 5 – Control voltage (CON) Prag glasnosti lahko nadzorujetetage (pin 6) preko krmilnega vhoda (ki je interno nastavljen na 2/3 napajalne napetostitage). Lahko ga spreminjate od 45 % do 90 % dobavljenega volumnatage. To vam omogoča spreminjanje dolžine izhodnega impulza v monostabilnem načinu ali izhodne frekvence v astabilnem načinu. Ko ni v uporabi, je priporočljivo, da je ta vhod priključen na ozemljitev vezja prek kondenzatorja 0.01 μF.
Pin 6 – Threshold (TRE) In both astable and monostable mode the voltagNapetost na časovnem kondenzatorju se spremlja preko vhoda praga. Ko je voltagKo se e pri tem vhodu dvigne nad pragovno vrednost, se bo izhod spremenil iz visoke v nizko vrednost.

Pin 7 – Discharge (DIS) when the voltagNapetost na časovnem kondenzatorju preseže pragovno vrednost. Časovni kondenzator se prazni preko tega vhoda.
Pin 8 – Supply voltage (VCC) To je pozitivna napetost napajanjatage terminal. Volumna napajalne napetostitagObmočje je običajno med +5 V in +15 V. Časovni interval RC se ne bo bistveno spreminjal glede na napajalno napetost.tagobmočju e (približno 0.1 %) v astabilnem ali monostabilnem načinu.

Monostabilno vezje

Slika 2 prikazuje osnovno monostabilno vezje časovnika 555.

Referring to the timing diagram in figure 3, a low voltagImpulz, ki se dovede na sprožilni vhod (pin 2), povzroči povečanje izhodne glasnosti.tage na pinu 3 za prehod iz nizke v visoko napetost. Vrednosti R1 in C1 določajo, kako dolgo bo izhod ostal visok.

During the timing interval, the state of the trigger input has no effect on the output. However, as indicated in Figure 3, if the trigger input is still low at the end of the timing interval, the output will remain high. Make sure that the trigger pulse is shorter than the desired timing interval. The circuit in figure 4 shows one way to accomplish this electronically. It produces a short-duration low-going pulse when S1 is closed. R1 and C1 are chosen to produce a trigger pulse that is much shorter than the timing interval.

As shown in figure 5, setting pin 4 (Reset) to low before the end of the timing interval will stop the timer.

Reset must return to high before another timing interval can be triggered.

Calculating the timing interval

Use the following formula to calculate the timing interval for a monostable circuit: T = 1.1 * R1 * C1
Where R1 is the resistance in ohms, C1 is the capacitance in farads, and T is the time interval. For example, if you use a 1M ohm resistor with a 1 micro Farad (.000001 F) capacitor the timing interval will be 1 second: T = 1.1 * 1000000 * 0.000001 = 1.1

Choosing RC components for Monostable operation

First, choose a value for C1.
The available range of capacitor values is small compared to resistor values. It’s easier to find a matching resistor value for a given capacitor.)
Next, calculate the value for R1 that, in combination with C1, will produce the desired timing interval.

Avoid using electrolytic capacitors. Their actual capacitance value can vary significantly from their rated value.
Also, they leak charge which can result in inaccurate timing values.

Instead, use a lower value capacitor and a higher value resistor. For standard 555 timers, use timing resistor values between 1K ohms and 1M ohms.

Monostabilno vezje Example

Figure 6 shows a complete 555 monostable multivibrator circuit with simple edge triggering. Closing switch S1 starts the 5-second timing interval and turns on LED1. At the end of the timing interval LED1 will turn off. During normal operation switch S2 connects pin 4 to the supply voltage. To stop the timer before the end of the timing interval, you set S2 to the “Reset” position which connects pin 4 to ground. Before starting another timing interval you must return S2 to the “Timer” position.

Astable Circuit

Figure 7 shows the basic 555 astable circuit.

In astable mode, capacitor C1 charges through resistors R1 and R2. While the capacitor is charging, the output is high.
Ko je voltage čez C1 doseže 2/3 dobavljenega volumnatage C1 discharges through resistor R2 and the output goes low.
Ko je voltage na C1 pade pod 1/3 dobavljenega volumnatagC1 nadaljuje s polnjenjem, izhod spet postane visok in cikel se ponovi.
Časovni diagram na sliki 8 prikazuje izhod časovnika 555 v astabilnem načinu.

Kot je prikazano na sliki 8, ozemljitev pina za ponastavitev (4) ustavi oscilator in nastavi izhod na nizek nivo. Vrnitev pina za ponastavitev na visok nivo ponovno zažene oscilator.
Izračun periode, frekvence in delovnega cikla Slika 9 prikazuje 1 celoten cikel kvadratnega vala, ki ga generira astabilno vezje 555.

The period (time to complete one cycle) of the square wave is the sum of the output high (Th) and low (Tl) times. That is: T = Th + Tl
kjer je T obdobje v sekundah.
You can calculate the output high and low times (in seconds) using the following formulas: Th = 0.7 * (R1 + R2) * C1 Tl = 0.7 * R2 * C1
or, using the formula below, you can calculate the period directly. T = 0.7 * (R1 + 2*R2) * C1
Če želite najti frekvenco, preprosto vzemite recipročno vrednost periode ali uporabite naslednjo formulo:

Kjer je f v ciklih na sekundo ali hercih (Hz).
Na primerampv astabilnem vezju na sliki 7, če je R1 68 kOhmov, R2 680 kOhmov in C1 1 mikrofarad, je frekvenca približno 1 Hz:

Delovni cikel je odstotektage časa, ko je izhod visok med enim celim ciklom. Na primerampČe je izhod visok Th sekund in nizek Tl sekund, potem je delovni cikel (D):

Vendar pa morate za izračun delovnega cikla poznati le vrednosti R1 in R2.

C1 se polni preko R1 in R2, prazni pa samo preko R2, zato bo delovni cikel večji od 50 odstotkov. Vendar pa lahko dosežete delovni cikel zelo blizu 50 % z izbiro kombinacije uporov za želeno frekvenco, tako da je R1 veliko manjši od R2.
Na primerampČe je R1 68,0000 ohmov in R2 680,000 ohmov, bo delovni cikel približno 52 odstotkov:

Manjši kot je R1 v primerjavi z R2, bližje bo delovni cikel 50 %.

Za dosego delovnega cikla manjšega od 50 % priključite diodo vzporedno z R2.

Choosing RC components for Astable operation

Choose C1 first.
Calculate the total value of the resistor combination (R1 + 2*R2) that will produce the desired frequency.
Select a value for R1 or R2 and calculate the other value. For examprecimo (R1 + 2*R2) = 50K in za R10 izberete upor 1K. Potem mora biti R2 upor 20K ohmov.

Za delovni cikel blizu 50 % izberite vrednost za R2, ki je bistveno višja od R1. Če je R2 velik glede na R1, lahko R1 v izračunih sprva zanemarite. Na primerampNpr. predpostavimo, da bo vrednost R2 10-kratnik R1. Za izračun vrednosti R2 uporabite to spremenjeno različico zgornje formule:

Nato rezultat delite z 10 ali več, da dobite vrednost za R1.
Za standardne časovnike 555 uporabite vrednosti časovnih uporov med 1K ohmi in 1M ohmi.

Astabilno vezje Example

Slika 10 prikazuje oscilator s kvadratnim valom 555 s frekvenco približno 2 Hz in delovnim ciklom približno 50 odstotkov. Ko je stikalo SPDT S1 v položaju »Start«, se na izhodu izmenično utripata LED 1 in LED 2. Ko je S1 v položaju »Stop«, LED 1 ostane prižgana, LED 2 pa izklopljena.

Različice z nizko porabo energije

The standard 555 has a few characteristics that are undesirable for battery-powered circuits.
It requires a minimum operating voltage of 5V and a relatively high quiescent supply current.

During output transitions, it produces current spikes of up to 100 mA. Additionally, its input bias and threshold current requirements impose a limit on the maximum timing resistor value, which limits the maximum time interval and astable frequency.
Low-power CMOS versions of the 555 timer, such as the 7555, TLC555 and the programmable CSS555, were developed to provide improved performance, especially in battery-powered applications.
They are pin compatible with the standard device, have a wider supply voltage obseg (nprample, 2V to 16V for the TLC555) and require significantly lower operating current.

They are also capable of producing higher output frequencies in astable mode (1-2 MHz, depending on the device) and significantly longer timing intervals in monostable mode.
These devices have low output current capability compared to the standard 555. For loads greater than 10 – 50 mA (depending on the device) you will need to add a current boost circuit between the 555 output and the load.

Za več informacij

Consider this a short introduction to the 555 timer.
For further information, be sure to study the manufacturer’s data sheet for the specific part that you are using.

Also, as a quick Google search will verify, there is no shortaginformacij in projektov, posvečenih tej integrirani shemi, na web.
Na primerample, naslednje website provides more detail on both standard and CMOS versions of the 555 timer www.sentex.ca/~mec1995/gadgets/555/555.html.

pogosta vprašanja

V: Kakšen je namen vhodov Trigger in Threshold v časovniku 555?

A: The Trigger input causes the output to go high when a low voltage is applied while the Threshold input stops the output from being high when a high voltage se uporablja.

V: Kakšen je priporočeni razpon vrednosti uporov za časovno nastavitev v standardnem časovniku 555?

A: It is recommended to use resistor values between 1K ohms and 1M ohms for accurate timing in a standard 555 timer configuration.

Dokumenti / Viri

Vadnica za časovnik Jameco 555 [pdf] Uporabniški priročnik
555 Vadnica za časovnik, 555, Vadnica za časovnik, Vadnica

Reference

Uporabniški priročnik

Vadnica za časovnik Jameco 555

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