# Help required in developing Pulse Generator

#### gargrahul277

Joined Apr 5, 2016
15
Hi all : )

I'm trying to build a circuit that will generate a pulse and need ur guidance in it

Refer the attached file for details of pulse.

Period of Pulse = 400 msec
Duty Cycle = 50%
With Two distinct voltage levels of 6 and 8 V.

first im trying to design the circuit on paper and need ur guidance in it to make sure im on right track

i plan to use 555 timer ic in astable mode and generate a pulse of 8V, period=400 msec with 50% duty cycle
but the low voltage level in this case is going to be 0 V. and not 6 V which is required.
so after timer ic i plan to connect a clipping circuit using diode which will clip the low voltage level to 6 V.

will this circuit work ??
is there any better idea(circuit) to generate the required pulse

#### Attachments

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#### Lestraveled

Joined May 19, 2014
1,946
It looks like a reasonable design. How exact do you need the output voltages to be?

Oh Yea, Welcome to the forum.

#### AnalogKid

Joined Aug 1, 2013
10,556
is there any better idea(circuit) to generate the required pulse
Depends on what this circuit is driving. Clipping the 555 output means using a current limiting resistor, which increases the overall circuit output impedance.

ak

#### dl324

Joined Mar 30, 2015
15,815
Welcome to AAC!

I'd suggest making your astable time period 200mS and use a flip flop to guarantee a 50% duty cycle in the 400mS waveform.

Depending on how accurate you need your logic levels to be, to get your 6V low, you could diode-OR 6V with the output of the timer (which should then have a supply voltage closer to 9V).

#### hp1729

Joined Nov 23, 2015
2,304
Hi all : )

I'm trying to build a circuit that will generate a pulse and need ur guidance in it

Refer the attached file for details of pulse.

Period of Pulse = 400 msec
Duty Cycle = 50%
With Two distinct voltage levels of 6 and 8 V.

first im trying to design the circuit on paper and need ur guidance in it to make sure im on right track

i plan to use 555 timer ic in astable mode and generate a pulse of 8V, period=400 msec with 50% duty cycle
but the low voltage level in this case is going to be 0 V. and not 6 V which is required.
so after timer ic i plan to connect a clipping circuit using diode which will clip the low voltage level to 6 V.

will this circuit work ??
is there any better idea(circuit) to generate the required pulse
Can you run the LM555 at +6V on the low rail instead of ground? Something like this. I haven't tried it yet.

#### Attachments

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Last edited:

#### wayneh

Joined Sep 9, 2010
17,405
..you could diode-OR 6V with the output of the timer....
Ditto. That's how I'd do it, assuming the timer output supplies enough current. If it needs an external transistor, it gets trickier but I'd still use diode ORing.