Timer to generate Vpulse

[Tamim]

Hi,
Iam want a timer with which i can generate vpulses. I know i can use
555 timer with two resistors and a capacitor but i dont think with
that i can control the delay time. Does anyone know how construct a
circuit so that not only i can adjust the period,hightime and low time
but also adjust the time at which my pulse would actualy start. i mean
the intial start time. Its important becuase in my project i have to
generate three vpulses each 120 degrees out of phase from the other.
If anyone has got any advice then PLEASE let me know ASAP.Thank u very
much in advance.
Best regards,
Tamim

 

[mike]

Hi,
Iam want a timer with which i can generate vpulses. I know i can use
555 timer with two resistors and a capacitor but i dont think with
that i can control the delay time. Does anyone know how construct a
circuit so that not only i can adjust the period,hightime and low time
but also adjust the time at which my pulse would actualy start. i mean
the intial start time. Its important becuase in my project i have to
generate three vpulses each 120 degrees out of phase from the other.
If anyone has got any advice then PLEASE let me know ASAP.Thank u very
much in advance.
Best regards,
Tamim

You can use 555s to delay different amounts to trigger other 555s.
But more importantly, what are you really trying to do.

Assume three separate pulse outputs?
Term "phase" implies frequency independence, which is a completely
different problem.

If you have control over the source, run it at 6X frequency and
digitally divide it to get the phase triggers. If you don't control
the source, that's a different problem.

Specificity!!!!
mike

--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Honda CB-125S $800 in PDX
TEK Sampling Sweep Plugin and RM564
Tek 2465 $800, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[Tamim]

Hi Mike,
Thanks for ur reply. Well u r right i didnt explain my problem
properly. Well the actual vpulses will be generated using square wave
excitation by using power mosfets and etc. I need these timers for my
gate drive circuits because i am using six power mosfets and i want
each one to open and close at my chosen times. as long as they do this
im happy!
Ur advice about using 555s to trigger different 555s is wat i had at
the back of my mind but as i have never used a timer in my life i was
not sure if i can do that. Now that u have told me i'll try it in
pspice to see wat happens. Thanx alot for ur advice.
Tamim