What is 555 Timer and its application?

What is 555 Timer and its application?

The 555 timer IC is an integrated circuit (chip) used in a variety of timer, delay, pulse generation, and oscillator applications. Derivatives provide two (556) or four (558) timing circuits in one package. Numerous companies have made the original bipolar timers and similar low-power CMOS timers too.

What are the types of 555 Timer?

There are two types of 555 timer based on its nomenclature – NE 555 Timer and SE 555 Timer. While NE 555 timer can be used in the temperature range from 0 to 70°C, the SE 555 Timer can be used in the temperature range from -55°C to 125°C and has a temperature stability of 0.005% per 0C..

What are the inputs and outputs of a 555 timer?

Figure 1 shows the input and output signals of the 555 timer as they are arranged around a standard 8 pin dual inline package (DIP). Pin 1 – Ground (GND) This pin is connected to circuit ground. A low voltage (less than 1/3 the supply voltage) applied momentarily to the Trigger input causes the output (pin 3) to go high.

How to calculate the duty cycle for a 555 timer?

Select a value for R1 or R2 and calculate the other value. For example, say (R1 + 2*R2) = 50K and you select a 10K resistor for R1. Then R2 must be a 20K ohm resistor. For a duty cycle close to 50%, select a value for R2 that is significantly higher than R1. If R2 is large relative to R1 you can initially ignore R1 in your calculations.

What are the characteristics of a 555 oscillator?

Figure 10: Complete 555 square wave oscillator circuit with start/stop switch. The standard 555 has a few characteristics that are undesirable for battery powered circuits. It requires a minimum operating voltage of 5V and relatively high quiescent supply current. During output transitions it produces current spikes of up to 100 mA.

Can a PNP be connected to a 555?

Do not connect a PNP to the output of a 555 as shown in the following diagram. Pin 3 does not rise high enough to turn off the transistor and the current taken by the circuit will be excessive. Use an NPN driver.