# Series or Parallel?

Discussion in 'General Electronics Discussion' started by SparkyCal, Aug 14, 2021.

1. ### SparkyCal

838
31
Mar 11, 2020
I am circling back to a project I undertook when I first got into electronics.

The project is to install a ring of LED lights around my guitar pickup.

I envision powering the lights with a 9 Volt battery. I probably will use 10 LEDs or so.

I realize that I will need a step down resistor, but I will deal with that soon. What I'd like to determine is whether it is better connecting. the LEDs to one another in parallel, or in series?

The idea would be to have them blink on and off and to shine at the same level of brightness.

Thank-you

2. ### SparkyCal

838
31
Mar 11, 2020
I have determined that I will be using 12 LEDs.

All of them have the following specs:

I/VF: 20mA/ 3-3.2V

3. ### Bluejets

5,530
1,163
Oct 5, 2014
If the LEDs are 3v2 each then you'll get 2 in series fron a 9v supply and add a series resistor to that.
2 x 3.2 = 6.4........ 9 - 6.4 = 2.6.......... 2.6V @ 20mA = ( I know, see if you can work it out) R = E/I
wattage = V x A or I squared R

The remainder need to be split into 5 banks of 2 LEDs and a resistor ( same arrangement as above) and placed in parallel with each set.

If your so-called 9v battery is a 216 style, (smoke alarm) forget it.
It'll drain the guts out of it in a few minutes if you are lucky.

Note that in many instances, the LED current can be halved without any large difference in brightness, depends on your needs I guess.

Martaine2005 likes this.
4. ### SparkyCal

838
31
Mar 11, 2020
Thanks Bluejets

I should better articulate my goal. The idea is to put a surround around my guitar pickup; much like putting a frame around a picture. On that frame will be leds so that when I flick a switch, the leds will blink. I had not considered the battery drain. The only saving grace is that it is to be used as an effect, sparIngly. It may be turNed on for a few seconds once every three songs or so.

5. ### Audioguru

3,601
758
Sep 24, 2016
A ring of LEDs that all blink on and off will be ho hum boring. Why not have them in a circuit that has a microphone that hears the guitar and makes the LEDs be bright during each strum. I would make the ring of LEDs be driven by a circuit that lights them in sequence for each strum like a VU meter. I made a LED VU meter and it shows sound levels in my living room.

6. ### SparkyCal

838
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Mar 11, 2020
That would be like asking me to bend the fabric of space/time. Lol. Besides, with a band, the mic would pick every thing up

7. ### Kabelsalat

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Jul 5, 2011
Well, no - making what Audioguru suggest are very doable in contrast to your other suggestion.

8. ### SparkyCal

838
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Mar 11, 2020
In a sense. However, a mic that has incredible isolation as to only respond to a single instrument amongst many, sounds impossible.

9. ### Bluejets

5,530
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Oct 5, 2014
A mic on an electric guitar is pretty pointless but one could pick up from the input to the amp or even direct from the pickup coils pre- mixer or whatever.
So is it acoustic or electric...??

10. ### Audioguru

3,601
758
Sep 24, 2016
Don't you have a speaker at your feet so you can hear what you are playing? Its speaker connection can drive an LED VU meter.
Kits for the VU meter are available.

11. ### SparkyCal

838
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Mar 11, 2020
Hey guys. I think we have gone from a ‘bling like’ device to flash my guitar’s pickup, to a colour organ driven by sound. I did not realize the led around the pickup would be as complex as it is. I would like to stick to the original idea, if it’s possible. As mentioned, it would be flashed on and off sparingly.

12. ### SparkyCal

838
31
Mar 11, 2020
Electric guitar, in this case. A Gibson studio Les Paul , to be exact. I have already built the little frame that the leds would sit on. I will post pics later

13. ### SparkyCal

838
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Mar 11, 2020
Please see the attached pic. You will notice a frame painted black, sitting between the two pickups. That frame will surround the chrome pickup that you see below where the frame is sitting now. My idea was to have LEDs on the frame (5 on top, 5 on bottom and two on either side_- so I guess 14 in total.

I was hoping to power it with a 9 volt battery, and wired to a small switch which is inconsopcious, that I can switch on or off during a performance.

It would be switched on briefly and sparingly.

Is this possible?

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14. ### Bluejets

5,530
1,163
Oct 5, 2014
Nice gear.....
as I said before, 9v battery as in smoke alarm (216) not enough capacity.
6 rungs of 20mA = ?
216 capacity = ?
mAh/mA = ?
again, I know, see if you can find out.

838
31
Mar 11, 2020
16. ### Audioguru

3,601
758
Sep 24, 2016
Here is how quickly a Name-Brand 9V alkaline battery will last:

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17. ### SparkyCal

838
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Mar 11, 2020
Thanks AG. That's good to understand. I think getting 40 minutes out of a battery is not bad, in the sense that it would likely cover one full night. 4 sets a night. Probably use it 5-10 minutes per set, if that.