# Help Reading a Cue Light Circuit Diagram and Suggestions

Discussion in 'The Projects Forum' started by robrobrob2, Apr 2, 2016.

1. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
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I am a student at my highschool and was wondering if I could get some help reading and understanding this diagram. I have already purchased a SPDT On-Off-On switch and have 9V batteries. My specific question is : how would I wire this up and is there room for improvement? This is the switch. Also How would this be grounded?

Thanks,

Student

2. ### ScottWang Moderator

Aug 23, 2012
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Is this a school homework or personal hobby?

3. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
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This is for school, but as it is not a homework assignment I thought I should not place it in the Homework Help category. Yes more of a hobby thing/one time project.

4. ### dannyf Well-Known Member

Sep 13, 2015
2,196
417
you will need to experiment. it looks like the middle pin on the switch connects to either of the on contacts.

If so, the middle pin goes to 9v and the on pins go to the two leds.

5. ### ScottWang Moderator

Aug 23, 2012
4,925
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If the vf of led is 3V/20mA then the resistor is ok, but if the vf of led is 2V/20mA then the resistor should be use 430.

6. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
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So if my switch only has three pins what would the positive and negative poles on the nine volt battery be connected to?

7. ### ScottWang Moderator

Aug 23, 2012
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777
Your first posted said that you only have one three pins switch (SPDT - Single-Pole, Single-Throw), and your circuit also shown the same, so what do you mean by that(if my switch only has three pins)?

And what are the XLR out and in, are they just three terminals?

If you are not using one switch has three pins, and now you want to use it then it is just like the connection in posted #5.

The XLR out and in, you can also use the stereo's jack plug and socket for the slave leds.

8. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
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Thank you so much guys

9. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
12
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All I was wondering was if the specific switch I have (linked in the original post as the word "switch") is the right or good switch?

10. ### ScottWang Moderator

Aug 23, 2012
4,925
777
It depends on what kind of function you want, the switch you that linked has 3 positions with center off, if you using it then you have as these functions:
1. Switch at the left side -- LED 1 light up.
2. Switch at the center -- Two LEDs off (center off function).
3. Switch at the right side -- LED 2 light up.

If you choosing other switches there is no center off function then you have as these functions:
1. Switch at the left side -- LED 1 light up.
2. Switch at the right side -- LED 2 light up.

11. ### GopherT AAC Fanatic!

Nov 23, 2012
6,304
4,029
It will work for the drawing in your first post, however, there is no indication that the switch stays on one flipped or if you have to hold it in each position (momentary switch). Finally, it is much heavier duty than needed . But will work.

12. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
12
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It is a non-momentary switch(stationary?).

13. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
12
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My last question is about the resistor. Is this(the one in the picture) a 390 Ohm resistor?

14. ### GopherT AAC Fanatic!

Nov 23, 2012
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If you mean the rectangle with "390" in it, yes, it is a resistor.

Nov 23, 2012
6,304
4,029
16. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
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I already have the switch I linked. I simply wondered if the resistor was 390 Ohms?

17. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
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Furthermore, I just wondered if the middle pin will be where the 9V battery's positive pole will connect to.

18. ### robrobrob2 Thread Starter New Member

Apr 2, 2016
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I know the vf is forward voltage, but does this mean the Voltage of the LED is 3V and it can withstand 20mA of power?

19. ### ScottWang Moderator

Aug 23, 2012
4,925
777
2V leds have 2V/10 mA/2mm, 2V/20 mA/3mm for normal light, and 3V Leds have 3V/10 mA/2mm, 3V/20 mA/3mm for high light.

20. ### hp1729 Well-Known Member

Nov 23, 2015
2,094
232
The drawing is kind of hard to follow. Your choice of switches is correct. SPDT, with a center off position. The drawing for that switch isn't very clear. Does this look better?

• ###### Design 508 Cue switch.pdf
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Last edited: Apr 6, 2016