Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

what's the difference between monostable and a stable

Status
Not open for further replies.

nutty boy

Member level 1
Joined
May 7, 2005
Messages
32
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,646
Hi
Can someone pls tell me what's the difference between monostable mode and astable mode in 555 timer circuits
 

IanP

Advanced Member level 5
Joined
Oct 5, 2004
Messages
7,942
Helped
2,311
Reputation
4,624
Reaction score
531
Trophy points
1,393
Location
West Coast
Activity points
66,416
Monostable will generate only one pulse; astable will generate a square wave.
In other words, monostable=one-shot, astable=free-running.
And 555 (indicated by Rectifier) is a very good example of both modes.
Regards,
IanP
 

power-twq

Full Member level 6
Joined
Jun 10, 2005
Messages
373
Helped
8
Reputation
16
Reaction score
3
Trophy points
1,298
Activity points
4,550
yes, what IanP said is quite right.

I'm very familar with 555 timer, it's

a great little IC, it has been invented for

about forty years. it has many use.

the monostable and astable are

two operating mode of a 555 timer.

and a 555 timer can be use as a RS latch.


now, talk about your question.

1) monostable : mean that the circuit has

a stable state. for 555 timer,

this state is low output state.

when a 555 timer use as a one-shot,

after a signal triggered the circuit,

the circuit will output a high level

pulse, then go back to low output state.

the pulse's width is determined by external

RC parameter.

2) astable: when a 555 timer use as a oscillator,

its output will swicthing between high state and

low state periodically, THE CIRCUIT DO NOT EXIST

A STABLE STATE if begin operate.

3) RS latch: when a 555 timer is used as a RS latch,

as we know, it will has two stable state,

high state and low state.

oh, perhaps it will exist a metastable state

in some special cases. but that beyond our

discussion.


best regards








nutty boy said:
Hi
Can someone pls tell me what's the difference between monostable mode and astable mode in 555 timer circuits
 

jeffttan

Member level 2
Joined
Jul 3, 2005
Messages
44
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,288
Activity points
1,671
monostable produces pulses when triggered. while astable doesnt need input trigger, it continuously generates pulses
 

No one

Full Member level 5
Joined
May 11, 2005
Messages
287
Helped
4
Reputation
8
Reaction score
2
Trophy points
1,298
Activity points
3,425
Hello;
I think that Jeffttan says true. A monostable multivibrator needs a trigger signal to produce an output pulse, but an astable multivibrator runs and needn't to be triggered for every output pulse. We can say that an astable multivibrator is an oscillator.
 

suvendu

Full Member level 3
Joined
Oct 10, 2004
Messages
169
Helped
16
Reputation
32
Reaction score
3
Trophy points
1,298
Activity points
2,121
monostable means which has one stable state.and bistable means two stable state,and another one is astable which has no stable state,these r three types of operation.astable mode is for oscillator.
 

kovic

Junior Member level 1
Joined
Jun 27, 2005
Messages
19
Helped
2
Reputation
4
Reaction score
1
Trophy points
1,283
Activity points
1,439
with the monostable you can use just one position. high level or low level. if you have low level you can use high level for once accordind to your input signal. you can vary the time for the high level by using a rc circuit. time is proportional with "r*c".
 
Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top