DE_MF

IC555 Pin diag

gram 7

7.2 MULTIVIBRATORS – A multivibrator is an electro a variety of simple two-state timers and flip-flops. It is ch devices (transistors, electr cross-coupled by resistors o The name \"multivibrator\" w running oscillator version of waveform was rich in harmo

– One shot onic circuit used to implement e systems such as oscillators, haracterized by two amplifying ron tubes or other devices) or capacitors.was initially applied to the free- f the circuit because its output onics. 8

• There are three types of m on the circuit operation: Bistable Monostable Astable

multivibrator circuits depending 9

 Astable - In which the circuit continually switches from one require an input such as a clock Monostable -In which one of th state is unstable (transient). A the unstable state. After enteri will return to the stable state a useful for creating a timing per to some external event. This cir

t is not stable in either state ite state to the other. It does notk pulse. he states is stable, but the other trigger causes the circuit to enter ing the unstable state, the circuitafter a set time. Such a circuit is riod of fixed duration in responsercuit is also known as a one shot. 10

 Bistable, in which the circui circuit can be flipped from external event or trigger.

it is stable in either state. The one state to the other by an 11

One Shot / Monos multivibratorT = 1.1 x R X C (Seconds)

stabler 12

7.3 Astable Multiv

vibratorsT =2C1R3ln (1+2R2/R1) 13

Astable Multivib An astable multivibrator is a which neither of the output l keeps on switching between is a periodic, rectangular wa therefore known as an ‗asta external trigger is required t output, hence it is also calle multivibrator‘.

brators: a wave-generating circuit in levels is stable. The output n the two unstable states and aveform. The circuit is able multivibrator‘. Also, no to change the state of the ed ‗free-running 14

7.4 Modes of operation and The 555 has three main ope Astable, and Bistable. Each type of circuit that has a par Astable mode An Astable Circuit has no st \"astable\". The output contin high and low without withou user, called a 'square' wave used to give a mechanism i switching a motor on and of also be used to flash lamps 'clock' pulse for other digital

Application: erating modes, Monostable,h mode represents a differentrticular output. table state - hence the namenually switches state betweenut any intervention from thee. This type of circuit could beintermittent motion by ff at regular intervals. It cans and LEDs, and is useful as a l ICs and circuits. 15

Astable

e mode 16