generating pulse

[prateek]

I need about 5% duty cycle pulse of about 1 sec time period. A second
pulse required should be of same characteristics but delayed by a
duration by about the 'on' time of the second pulse. ie the first
pulse should go on and then the secoond pulse should go on. Need a
simple solution please

 

[Mochuelo]

I need about 5% duty cycle pulse of about 1 sec time period. A second
pulse required should be of same characteristics but delayed by a
duration by about the 'on' time of the second pulse. ie the first
pulse should go on and then the secoond pulse should go on. Need a
simple solution please

Cheapest is a microcontroller running on its internal RC oscillator,
which you may have more or less calibrated.

If you don't want to use microcontrollers, you can use a 1 Hz
oscillator that feeds a monostable that generates 50 ms wide, high
logic-level pulses. A second monostable is set to trigger on the
high-to-low transitions of the first monostable's output, and also
generates 50 ms wide, high logic-level pulses. You can do the whole
thing with a 40106 (hex inverter with schmitt-trigger), three
capacitors, three resistors and two diodes, as shown in the figure.

http://80.35.195.131/ng/ng_20060623A01.png

R1 & C1 such that period is 1 s.
R2 & C2 such that A and B pulses are 50 ms wide.
D1 can be 1N4148.

Best,

 

[Tim Williams]

So, you want:
___
Trig ___| . . . (doesn't matter?)
__________
A ___| |________________ . . . (until next trigger)
__________
B ______________| |_____ . . .

???

You can do that with two of these.
http://webpages.charter.net/dawill/Images/One-shot Timer.gif
Trig is the input. Connect Q' (Q bar) to Trig of the second one. Use Q
from each for the "A" and "B" output above. Adjust Rt and Ct for one
second.

Tim

 

[ehsjr]

I need about 5% duty cycle pulse of about 1 sec time period. A second
pulse required should be of same characteristics but delayed by a
duration by about the 'on' time of the second pulse. ie the first
pulse should go on and then the secoond pulse should go on. Need a
simple solution please

_ _ _ _
| | | | | | | |
-- -- --------------------- -- ---
T 0 1 2 3 Repeat

So you want T0-T1 = 50 mS, T1-T2 = 50mS,
T0-Repeat = 1000 mS?

Count to 20 in 50 mS steps (drive 4017's with
a 555 running at 20 hZ, set the 4017 chain
to reset at count 20). Use counter output 0 and
2 for your pulses. Actually you can use any
pair of counts such that there is one count
between them, like 1 and 3, 2 and 4, 3 and 5, etc.

Ed