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An IC 4013

malc9141

Member
Hi Guys

Please accept that, tho' an expert in a number of areas, electronics isn't one of them. I can't even draw a diagram! So, my very elementary question is asked with due humility and I hope for a sympathetic answer.

I have a fixed duration square wave pulse coming out of a 555 unit. It must activate one circuit, then an independent twin circuit, and then back again. Call one circuit A, the other, B.

So I have 12 v at Pin 14; output A at Pin 1: output B at Pin 2; Gnd at Pin 7.
But where does my 555 pulse come in? I presume Pin 3.
Where do the other Pins (3, 4, 5, 6) go?

Thank you!

Malc9141
 

ronsimpson

Well-Known Member
Most Helpful Member
1601163276703.png
Set1 and Reset1 to ground.
Data1 to /Q1
All unused inputs go ground or supply.
Unused output leave open.
Clock is from the 555.
 
Last edited:

eTech

Active Member
Hi Guys

Please accept that, tho' an expert in a number of areas, electronics isn't one of them. I can't even draw a diagram! So, my very elementary question is asked with due humility and I hope for a sympathetic answer.

I have a fixed duration square wave pulse coming out of a 555 unit. It must activate one circuit, then an independent twin circuit, and then back again. Call one circuit A, the other, B.

So I have 12 v at Pin 14; output A at Pin 1: output B at Pin 2; Gnd at Pin 7.
But where does my 555 pulse come in? I presume Pin 3.
Where do the other Pins (3, 4, 5, 6) go?

Thank you!

Malc9141
Try to draw a simple timing diagram to show the relationship of the 555 output pulse and the state of circuit A and B outputs. The horizontal axis would represent “time” and the vertical axis would represent the on/off states of the 555 and A and B circuits.

then we can design the circuit.
 

gophert

Well-Known Member
Most Helpful Member

malc9141

Member
Hi People

If I have a square wave falling pulse feeding the 555, as shown in diagram above, how can I variably delay the input or output by between 0 and 2 ms (0.002 s)? Obviously a simple R and C would be too crude.

Thanks

Malc9141
 

eTech

Active Member
Hi People

If I have a square wave falling pulse feeding the 555, as shown in diagram above, how can I variably delay the input or output by between 0 and 2 ms (0.002 s)? Obviously a simple R and C would be too crude.

Thanks

Malc9141

Trim1 sets the output delay of the 555. If its too long or too short, R1, R2, Trim1 and C4 may need to be recalculated to achieve the desired delay. If you need to delay the input, configure a second 555 for the desired delay. Then connect the output of the additional 555 to the input of the existing 555.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
The trigger input on a 555 is a schmitt trigger with a fixed threshold (% supply voltage).

As long as the signal feeding that is also a fixed voltage, then a simple R-C delay with a medium value pot (10k?) and low value cap should give a very consistent, variable, delay.

Edit - this, with a variable resistor & appropriate cap.
The 555 becomes the right hand gate, the left part is any appropriate logic level drive signal.

 

malc9141

Member
Many thanks. Can it really be that simple!
In your diagram (thanx again), is the Schmitt trigger at the Pin 3 on the 555?
Your R1 is a variable resistor?
 

gophert

Well-Known Member
Most Helpful Member
Many thanks. Can it really be that simple!
In your diagram (thanx again), is the Schmitt trigger at the Pin 3 on the 555?
Your R1 is a variable resistor?
Yes, it is that easy.
No, the 10k is fixed. 10k x 1nF is 0.01mSec time constant - no reason to adjust.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
Both the trigger and threshold pins on a 555 are schmitt trigger inputs, so can work from slowly changing signals.

For 0-2 mS, you would need 200nF and a 10K pot; or 20nF and a 100K pot, which would put less load on the previous output.
(220nF or 22nF in practice, as standard values).
 

gophert

Well-Known Member
Most Helpful Member
When you ask for a 0-2mSec delay, do you mean you want a signal that exactly tracks your master signal but is delayed by 0 to 2mSec? (Ups and downs?).

or, is your device on the delayed line only concerned about the rising edges. That is, the rising edges of the slave (Delayed) signal should follow the master signal by 0. To 2mSec but the falling edges can be any duration?

also,
what is the minimum time the master signal is high?

Is it ever high for less than 2mSec? Is it ever low for less than 2mSec?
 

malc9141

Member
do you mean you want a signal that exactly tracks your master signal but is delayed by 0 to 2mSec? (Ups and downs?)
Almost this. I can set the incoming signal at Zero time and delay output 0 - 2 ms.
The input is from a 4093, because the falling edge from the sensor, which goes to 0v, is a bit doubtful as to sharpness. So you can tell me if the 555 is
"seeing" a rise or a fall - but it's sharp. It's a matter of what triggers the 555. Then so delays the 555's output.
what is the minimum time the master signal is high (low, actually)
I don't know, but its long w.r.t. the minimum delay. However, that doesn't matter, surely, if the trigger has happened.
 

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