pulse detector

[Mono Electronic]

hi friends
i need a circuit that detect a pulse .the pulse value is 12v max and 0v in minimum.when circuit detect the pulse,the output is "1" and when input circuit is 12v or 0v,circuit output is 0v.
please help me.

 

[alec_t]

If the output is 0V when the input pulse is at 12V and at 0V, at what voltage do you want the detector to be triggered?
What is the pulse duration?
Is it repetitive?
A standard logic gate may meet your requirements.

 

[Mono Electronic]

If the output is 0V when the input pulse is at 12V and at 0V, at what voltage do you want the detector to be triggered?
What is the pulse duration?
Is it repetitive?
A standard logic gate may meet your requirements.

oh...yes...i forget this.
the maximum frequency is 100Hz.if circuit detect a pulse with 1Hz freq the output to "1"....of course i want to make this circuit whit 555 IC.

 

[alec_t]

At what voltage do you want the detector to be triggered (since it can't be 0V and it can't be 12V)?
What is the 555 for? That needs a negative-going pulse to trigger it.

 

[Mosaic]

The OP might be talking about pulse stretching.

 

[cowboybob]

hi friends
i need a circuit that detect a pulse .the pulse value is 12v max and 0v in minimum.when circuit detect the pulse,the output is "1" and when input circuit is 12v or 0v,circuit output is 0v.
please help me.

By your description, this sounds more like a job for a comparator circuit (OFF or "0", at 0VDC and 12VDC, ON or "1", at some voltage between 0VDC and 12VDC).

Have I (and alec_t) described your intended circuit response correctly? If we have, you can make a decent comparator with 2 Op Amps, a 555 timer and associated discrete components. I would be glad to provide a working schematic.

 

[surbhit]

put a ceramic capacitor 0.01uf or 0.1uf in series you will get short period pulse.

 

[crutschow]

Exactly what are you trying to do? It's not at all clear.

 

[Tony Stewart]

This is the basic job of a comparator which accepts any analog input and reference ( perhaps scaled down to not exceed input range , if using low voltage V) and outputs open collector that you may pull-up R to the correct logic level or has complementary drivers to standard logic levels.

Required:
1) Input pulse width min.. depends on comparator choice of bandwidth from low tech. 500kHz to high tech > 1 GHz.
2) Ideal threshold for input 0/1 = V/2?
3) Output pulse width min
4) Voltage for "1"