555 Timer IC Pin Diagram & Specifications

By IKTech July 23, 2017

The 555 clock IC is a vital piece of hardware ventures. Be it a basic venture including a solitary 8 bit small scale controller and a few peripherals or a mind boggling one including framework on chips (SoCs), 555 clock working is included. These give time delays, as an oscillator and as a flip-flounder component among different applications.

Presented in 1971 by the American organization Signetics, the 555 is still in across the board use because of its low value, usability and steadiness. It is made by many organizations in the first bipolar and low-control CMOS sorts. As per a gauge, a billion units were made back in the year 2003 alone. (That time, just 555 i knew was a hack syrup).


Contingent upon the producer, the standard 555 bundle incorporates 25 transistors, 2 diodes and 15 resistors on a silicon chip introduced in a 8-stick smaller than normal double in-line bundle (DIP-8). Variations comprises of joining various chips on one board. However 555 is as yet the most well known. We should take a gander at the stick outline to have a thought regarding the clock IC before we discuss 555 clock working.



555 Timer IC: square chart

555 clock working: stick setup

8 stick DIP arrangement

Stick chart and depiction

Pin Name Purpose

1 GND Ground reference voltage, low level (0 V)


The OUT stick goes high and a planning interim begins when this information falls beneath 1/2 of CTRL voltage (which is normally 1/3 Vcc, CTRL being 2/3 Vcc naturally if CTRL is left open). At the end of the day, OUT is high as long as the trigger low. Yield of the clock thoroughly relies on the abundancy of the outside trigger voltage connected to this stick.

3 OUT This yield is headed to around 1.7 V beneath +Vcc, or to GND.


A planning interim might be reset by driving this contribution to GND, however the planning does not start again until the point when RESET transcends around 0.7 volts. Abrogates TRIG which supersedes edge.


Gives “control” access to the inside voltage divider (as a matter of course, 2/3 Vcc).


The planning (OUT high) interim closures when the voltage at limit is more noteworthy than that at CTRL (2/3 Vcc if CTRL is open).


Open gatherer yield which may release a capacitor between interims. In stage with yield.

8 Vcc

Positive supply voltage, which is as a rule in the vicinity of 3 and 15 V relying upon the variety.

Some imperative components of the 555 clock:

555 is utilized as a part of practically every electronic circuit today. For a 555 clock filling in as a flip slump or as a multi-vibrator, it has a specific arrangement of designs. A portion of the real components of the 555 would be,

It works from an extensive variety of energy running from +5 Volts to +18 Volts supply voltage.

Sinking or sourcing 200 mA of load current.

The outer parts ought to be chosen legitimately so the planning interims can be made into a few minutes alongside the frequencies surpassing a few hundred kilo hertz.

The yield of a 555 clock can drive a transistor-transistor rationale (TTL) because of its high current yield.

It has a temperature solidness of 50 sections for each million (ppm) per degree Celsius change in temperature which is proportionate to 0.005 %/°C.

The obligation cycle of the clock is customizable.

Additionally, the most extreme power dispersal per bundle is 600 mW and its trigger and reset inputs has rationale similarity.

555 clock working

The 555 for the most part works in 3 modes. A-steady, Mono-stable and Bi-stable modes.

Astable mode

This implies there will be no steady level at the yield. So the yield will be swinging amongst high and low. This character of precarious yield is utilized as clock or square wave yield for some applications.

Mono-stable mode

This setup comprises of one steady and one temperamental state. The steady state can be picked either high or low by the client. On the off chance that the steady yield is set at high(1), the yield of the clock is high(1). At the use of an intrude on, the clock yield turns low(0). Since the low state is flimsy it goes to high(1) consequently after the intrude on passes. Comparative is the situation for a low stable mono-stable mode.

Bi-stable mode

In bi-stable mode, both the yield states are steady. At each intrude on, the yield changes from low(0) to high(1) and the other way around, and remains there. For instance, in the event that we have a high(1) yield, it will go low(0) once it gets a hinder and stay low(0) till the following intrude on changes the status.

This datasheet ought to give a knowledge into the specifics: 555 Timer IC

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