DRL Logic question

1. May 5, 2013

Ahmedzica

Hi Guys,

I'm solving a DRL related problem

https://dl.dropboxusercontent.com/u/49829206/skitch.jpg [Broken]

I though the output diode were in forward . but I suddenly noticed that it's in reverse .. so I couldn't handle the answer. can anybody help,please?

Last edited by a moderator: May 6, 2017
2. May 5, 2013

Staff: Mentor

Your pic is not viewable by the public.

3. May 5, 2013

Ahmedzica

oh Sorry ... here is it

https://dl.dropboxusercontent.com/u/49829206/skitch.jpg [Broken]

Last edited by a moderator: May 6, 2017
4. May 5, 2013

5. May 5, 2013

phinds

Just as a general note, when you ask someone to do you a favor (like answering a question for you), it's not really a good idea to make it difficult for them (by, for example, posting a picture sideways so that it is very hard to read).

Last edited by a moderator: May 6, 2017
6. May 5, 2013

Ahmedzica

yes you're right .. I'm sorry

7. May 5, 2013

8. May 5, 2013

Staff: Mentor

Ah, so it is. That causes me to conclude you have drawn it incorrectly, as I can see yours not functioning properly with that diode blocking the output. What do your classmates think?

◗ Where you wrote Vcc - I1R, can you describe the path I takes through your circuit?

◗ For inputs 1 0 0 I'd be inclined to estimate Vx as a little higher than 0.7V to distinguish that condition from some others (such as 0 1 1). Can you account for this?

◗ You gave one resistor a value, do you need to estimate a value for the other resistor, too?

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9. May 5, 2013

Staff: Mentor

10. May 6, 2013

Ahmedzica

yes that's what I thought.. I solved it as the one right here
http://people.seas.harvard.edu/~jones/es154/lectures/lecture_7/DL_DTL/ls_dl.jpg

11. May 6, 2013

Ahmedzica

what do you think of this

https://dl.dropboxusercontent.com/u/49829206/Photo%20May%2006%2C%205%2007%2025%20PM.jpg [Broken]

I've solved it but I can not know what is the function of D2 and D3, could you tell me,please?

Last edited by a moderator: May 6, 2017
12. May 7, 2013

Staff: Mentor

I don't know what the purpose of D2 is. But as this circuit does not fit under the heading "DRL Logic question" I think you should post it as a separate thread. Other students interested in this transistor logic would not find it under the current header.

Last edited by a moderator: May 6, 2017