Jameco 555 Timer Tutoriaal Gebruikersgids

Jameco 555 Timer Tutoriaal

Produk inligting

Spesifikasies

• Produknaam: 555 Timer IC
• Bekendgestel: Meer as 40 jaar gelede
• Functions: Timer in monostable mode and square wave oscillator in astable mode
• Pakket: 8-pen DIP

Produkgebruiksinstruksies

• Verbind Pen 1 (Aarde) met stroombaangrond.
• 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.
• Vermy die gebruik van elektrolitiese kapasitors vir akkurate tydsberekening.
• Use resistor values between 1K ohms and 1M ohms for standard 555 timers.
• Verbind Pen 1 (Aarde) met stroombaangrond.
• Capacitor C1 charges through resistors R1 and R2 in astable mode.
• Die uitset is hoog terwyl die kondensator laai.
• Uitset gaan laag wanneer die volumetage oor C1 bereik 2/3 van die aanbodvolumetage.
• Uitset gaan weer hoog wanneer die volumetage oor C1 daal onder 1/3 van die aanbodvolumetage.
• Grounding Pin 4 (Reset) stops the oscillator and sets the output to low.

Hoe om 'n 555-timer-IC te konfigureer

555 Timer Tutoriaal
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.

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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).

• Pen 1 – Aarde (GND) Hierdie pen is aan die stroombaangrond gekoppel.
• Pen 2 – Sneller (TRI) 'n Lae volumetage (minder as 1/3 van die toevoervolume)tage) as dit kortliks op die sneller-inset toegepas word, word die uitset (pen 3) hoog. Die uitset sal hoog bly totdat 'n hoë volume bereik word.tage word toegepas op die Drempel-inset (pen 6).
• Pin 3 – Output (OUT) In the output low state the voltage will be close to 0V. In the output high state the voltage sal 1.7V laer wees as die toevoervolumetage. Byvoorbeeldample, indien die toevoervolumetage is 5V uitset hoë voltage sal 3.3 volt wees. Die uitset kan tot 200 mA genereer of sink (maksimum hang af van die toevoervolume)tagen).

• Pin 4 – Reset (RES) A low voltage (minder as 0.7V) wat op die herstelpen toegepas word, sal veroorsaak dat die uitset (pen 3) laag gaan. Hierdie inset moet aan Vcc gekoppel bly wanneer dit nie gebruik word nie.
• Pin 5 – Control voltage (CON) Jy kan die drempelvolume beheertage (pen 6) deur die beheerinset (wat intern op 2/3 van die toevoervolume gestel is)tage). Jy kan dit wissel van 45% tot 90% van die voorsieningsvolumetage. Dit stel jou in staat om die lengte van die uitsetpuls in monostabiele modus of die uitsetfrekwensie in astabiele modus te varieer. Wanneer dit nie gebruik word nie, word dit aanbeveel dat hierdie inset via 'n 0.01uF-kondensator aan die stroombaangrond gekoppel word.
• Pin 6 – Threshold (TRE) In both astable and monostable mode the voltage oor die tydsberekeningskondensator word gemonitor deur die Drempel-inset. Wanneer die voltage wanneer hierdie inset bo die drempelwaarde styg, sal die uitset van hoog na laag gaan.
• Pin 7 – Discharge (DIS) when the voltage oor die tydkondensator oorskry die drempelwaarde. Die tydkondensator word deur hierdie invoer ontlaai.
• Pin 8 – Supply voltage (VCC) Dit is die positiewe aanbodvolumetage-terminaal. Die toevoervolumetagDie reeks is gewoonlik tussen +5V en +15V. Die RC-tydsinterval sal nie veel wissel oor die toevoervolume nie.tage-reeks (ongeveer 0.1%) in óf astabiele óf monostabiele modus.

Monostabiele stroombaan

Figuur 2 toon die basiese 555-timer monostabiele stroombaan.

• Referring to the timing diagram in figure 3, a low voltagDie puls wat op die snellerinvoer (pen 2) toegepas word, veroorsaak die uitsetvolume.tage by pen 3 om van laag na hoog te gaan. Die waardes van R1 en C1 bepaal hoe lank die uitset hoog sal bly.

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

1. 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.)
2. 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.

Monostabiele stroombaan 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.
• Wanneer die voltage oor C1 bereik 2/3 van die aanbodvolumetage C1 discharges through resistor R2 and the output goes low.
• Wanneer die voltage oor C1 daal onder 1/3 van die aanbodvolumetage C1 hervat laai, die uitset word weer hoog en die siklus herhaal.
• Die tyddiagram in figuur 8 toon die 555-tydtelleruitset in astabiele modus.

• Soos in figuur 8 getoon, stop die aarding van die Herstelpen (4) die ossillator en stel die uitset na laag. As die Herstelpen terug na hoog gestel word, herbegin die ossillator.
• Berekening van die periode, frekwensie en werksiklus Figuur 9 toon 1 volledige siklus van 'n vierkantige golf wat deur 'n 555 astabiele stroombaan gegenereer word.

• 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
• waar T die periode is, in sekondes.
• 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
• Om die frekwensie te vind, neem net die omgekeerde van die periode of gebruik die volgende formule:

• Waar f in siklusse per sekonde of hertz (Hz) is.
• Byvoorbeeldample, in die astabiele stroombaan in figuur 7, as R1 68K ohm is, R2 680K ohm is, en C1 1 mikro Farad is, is die frekwensie ongeveer 1 Hz:

• Die dienssiklus is die persentasietagdie tyd wat die uitset hoog is gedurende een volledige siklus. Byvoorbeeldample, as die uitset hoog is vir Th sekondes en laag vir Tl sekondes, dan is die werksiklus (D):

• Jy hoef egter net die waardes van R1 en R2 te ken om die werksiklus te bereken.

• C1 laai deur R1 en R2, maar ontlaai deur R2 alleen, dus sal die werksiklus groter as 50 persent wees. Jy kan egter 'n werksiklus baie naby aan 50% verkry deur 'n weerstandkombinasie vir die verlangde frekwensie te kies sodat R1 baie kleiner as R2 is.
• ByvoorbeeldampAs R1 68,0000 2 ohm is en R680,000 52 XNUMX ohm, sal die werksiklus ongeveer XNUMX persent wees:

• Hoe kleiner R1 in vergelyking met R2 is, hoe nader sal die werksiklus aan 50% wees.
• Om 'n werksiklus van minder as 50% te verkry, koppel 'n diode parallel met R2.

Choosing RC components for Astable operation

1. Choose C1 first.
2. Calculate the total value of the resistor combination (R1 + 2*R2) that will produce the desired frequency.
3. Select a value for R1 or R2 and calculate the other value. For exampd.w.s. (R1 + 2*R2) = 50K en jy kies 'n 10K weerstand vir R1. Dan moet R2 'n 20K ohm weerstand wees.

Vir 'n werksiklus naby 50%, kies 'n waarde vir R2 wat aansienlik hoër is as R1. As R2 groot is relatief tot R1, kan jy aanvanklik R1 in jou berekeninge ignoreer. Byvoorbeeldample, neem aan dat die waarde van R2 10 keer R1 sal wees. Gebruik hierdie gewysigde weergawe van die bogenoemde formule om die waarde van R2 te bereken:

• Deel dan die resultaat deur 10 of meer om die waarde vir R1 te vind.
• Vir standaard 555-tydtellers, gebruik tydweerstandwaardes tussen 1K ohm en 1M ohm.

Astabiele stroombaan Example

Figuur 10 toon 'n 555 vierkantsgolf-ossillator met 'n frekwensie van ongeveer 2 Hz en 'n werksiklus van ongeveer 50 persent. Wanneer SPDT-skakelaar S1 in die "Begin"-posisie is, wissel die uitset tussen LED 1 en LED 2. Wanneer S1 in die "Stop"-posisie is, sal LED 1 aan bly en LED 2 sal af bly.

Lae-krag weergawes

• 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 reeks (bvample, 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.

Vir meer inligting

• 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 shortage van inligting en projekte gewy aan hierdie IC oor die web.
• Byvoorbeeldample, die volgende website provides more detail on both standard and CMOS versions of the 555 timer www.sentex.ca/~mec1995/gadgets/555/555.html.

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