Humbucker phase testing

[Sock Puppet]

I put together a simple test bed for checking pickup coil phase - schematic to follow.

Having checked for coil problems and establishing continuity of the coils, the coils Black/White and Red/Green are connected to the inputs.

I haven't any idea how to put subtitles on the video so:

0:08 Slug side (North) White is +Ve going w.r.t. Black
0:15 Screw side (South) shows Green is +Ve going w.r.t. Red
0:20 A satisfying clout shows both coils together

Normally this pickup would be wired Black ground, Red+White together, Green hot. You could reverse the Green and Black here and swap the phase.

It could also be wired with Green to Black and either White or Red to Ground etc if you need it.

I won't bother with parallel wiring here.

[David King]

So please tell us more about the circuit behind the curtain if you would.

And also what brand of chisel you are using...

[Lollar Jason]

looks like a stanley or a buck :{>

[Sock Puppet]

First off, the chisel is an Irwin.Marples 3/4" MS500 All-Purpose Chisels with Striking Cap - Tools - IRWIN TOOLS

- though a steel rule works too.

The circuit mess that was hiding has devolved and lost a few components since that video but currently looks a bit like this - I tried a couple of zeners across 12V for a single rail supply and tried 9-0-9 with LED resistors. There were also larger capacitors with 10M bleed resistors initially.

As it stands now, it works well and the gate capacitors are discharged by leakage through the zeners. I like the zeners in place to help protect the mosfets. LED current is limited by the small batteries, max. current is under 6mA per side.

Had a bit of trouble drawing the dots where connections are so it's not perfect (& not elegant either)

[David King]

Holy smokes, that looks so professional dots or no dots. Thanks for posting it! I didn't recognize the mosfet's symbols but I guess they are some sort of transistor or gate thing? Zeners are diodes that let current through above a certain voltage? It's been 35 years since the last electronics class I took in high school.
i was thinking the caps were there to keep the LEDs on a little longer but it's more of a timer circuit than actual energy storage device.

[the great waldo]

Hi Sock puppet

What happens when one of the coils is wired out of phase ?

Cheers

Andrew

[Sock Puppet]

Yes, the capacitors are there to keep the LEDs on a short while and the zeners protect against any unwanted high voltages at the sensitive gates.

The transistor symbols are enhancement mode MOSFETs, I just used what I had in the box with the N channel ones at the top being BUZ72L and the lower P channel was a dual one in a tiny package - APM4953.

I was lucky to have these as they have a low threshold voltage on the base.

I tried 16V zeners in today the LEDs are lit for longer, something to play with.

The diagram was my first attempt with the free SchemeIt on the Digikey site here:

http://www.digikey.com/schemeit/?la=en

[Sock Puppet]

Hi Sock puppet

What happens when one of the coils is wired out of phase ?

Cheers

Andrew

Hi Andrew.

From the video, the Green/Blue LED pair associated with that coil will be reversed, so the Blue will light when the chisel goes toward the pickup coil.

Now reversing those coil leads would put the pickup in phase with Hot Positive Going (only way I can describe it)
If instead you reverse the other coil so that the Blue LEDs light with chisel going towards the coils then the pickup will be in phase with Hot Negative Going.

Hope that makes sense, looks like gibberish :-)

[David King]

Would it be possible to refine the design with bi-colored LEDs, say Red/Green for in/out of phase? I'm not sure if the current is reversing direction here or not.

My EE friend suggested I use an LM311 and send a test signal through the coils to check for phase at the output. I'm not well read enough to figure that all out but it might mean something to someone else.

[the great waldo]

Would it be possible to refine the design with bi-colored LEDs, say Red/Green for in/out of phase? I'm not sure if the current is reversing direction here or not.

My EE friend suggested I use an LM311 and send a test signal through the coils to check for phase at the output. I'm not well read enough to figure that all out but it might mean something to someone else.

I would agree with that idea David.

Cheers

Andrew

[Sock Puppet]

Meh... It's off my bench now.

[copperheadroads]

And also what brand of chisel you are using...

Now there's a Woodworker

[copperheadroads]

Wow nice project
can i do up a layout on vero/stripboard & post it ?

[Sock Puppet]

Wow nice project
can i do up a layout on vero/stripboard & post it ?

It's all yours, check your PM

[David King]

I'm starting a new thread in the "tools/winders" section to see if we can launch a group project with this. I'd like so see a bit more functionality to this gizmo and perhaps if we put our heads together we could come up with a really useful tool that could become a groupbuy etc.