# 4528 Dual Monostable Circuit

#### Stackington21

Joined Oct 16, 2015
11
Wondering if i can get some assistance for a task i have been given for uni, it is supposed to help coming into the exam. So the information is limited i am finding on this but we are asked to "Use a single 4528 Dual Monostable to construct an astable circuit with a mark-space ration of 0.5 and times of the order of 1 to 2 seconds, Put indicating LED's on the circuit to indicate both times."

So far (my understandings) are that one monostable could possibly trigger the other monostable to give the appropriate waveforms & the mark-space time means the high time to the low time.

Any help on this would be appreciated. I have attached the 4528 data sheet for reference.

Thanks

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#### GopherT

Joined Nov 23, 2012
8,012
Wondering if i can get some assistance for a task i have been given for uni, it is supposed to help coming into the exam. So the information is limited i am finding on this but we are asked to "Use a single 4528 Dual Monostable to construct an astable circuit with a mark-space ration of 0.5 and times of the order of 1 to 2 seconds, Put indicating LED's on the circuit to indicate both times."

So far (my understandings) are that one monostable could possibly trigger the other monostable to give the appropriate waveforms & the mark-space time means the high time to the low time.

Any help on this would be appreciated. I have attached the 4528 data sheet for reference.

Thanks
I know your professor is asking you to do it with this particular chip so you have to give this some thought. From my point of view, however, I would tell him I would use a 4528 to make this circuit by taking the 4528 to a local HAM swap meet and trading it for a CD4047 or a 555 timer and build a circuit scoring to the datasheet.

Anyhow, you are on the right track with the two in a loop - re triggering each other. You just need a push button to start it off.

#### Stackington21

Joined Oct 16, 2015
11
So i have found how the circuit should work and the led part of the circuit is sorted. As for the "mark-space ration of 0.5 and times of the order of 1 to 2 seconds", i am not exactly sure what is meant by that? With an order of say 1 second, i assuming the mark space ratio should be 0.5 seconds.

By using the K*R1*C1 to equal 0.5 seconds should covered that off? I have found the K value to be 0.32 when Vcc is +10V and assuming value for C1 is 220uF

Cheers

#### GopherT

Joined Nov 23, 2012
8,012
So i have found how the circuit should work and the led part of the circuit is sorted. As for the "mark-space ration of 0.5 and times of the order of 1 to 2 seconds", i am not exactly sure what is meant by that? With an order of say 1 second, i assuming the mark space ratio should be 0.5 seconds.

By using the K*R1*C1 to equal 0.5 seconds should covered that off? I have found the K value to be 0.32 when Vcc is +10V and assuming value for C1 is 220uF

Cheers
I think he meant RATIO, not Ration. And, then you would be correct. Mark means high (on) and Space means low (off). That terminology goes back to Morse Code days.

Good luck

#### Alec_t

Joined Sep 17, 2013
13,077
So,
Mark-space ratio = time high / time low.
Period = time high per cycle + time low per cycle

#### coanh5496

Joined Jul 30, 2016
1
Hi,
How did you get the answer 0.5 out of that equation K*R1*C1? How do we define K in this case? And what does the "times of the order of 1 to 2 seconds" have to do with the outcome frequency?
Sorry to ask this much but I'm also struggling with this same problem.

Thanks and regards,
George