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uBITX BAT54SL: diode ring mixer direction question


Michael LeBlanc
 

I'm building a uBITX from scratch and I noticed that in the schematic for the BAT54SL, Farhan has shown the component as having the cathode at pin 1 and anode at pin 2. However, the ON Semiconductor datasheet for this component has the anode at pin 1 and cathode at pin 2. On the schematic, for example, the mixer between T4 and T3 has the diode arrows going around in a clockwise direction.

If the datasheet is correct and this is indeed the proper configuration for this component, then the schematic appears to be in error. 

So my question: is the direction of the diode ring is significant? Is the clockwise direction essential for proper operation of this circuit--are the pin numbers incorrect--or can can I successfully wire up the transformer toroids to the pins of the diodes as shown in Farhan's schematic, forgetting about what's actually inside these tiny black boxes?

-Michael VE1LEB


 

It doesn't matter if pins 1/3 are interchanged. Both pairs must be similarly interchanged.

Good luck with your build!

Raj


At 31/03/2018, you wrote:
I'm building a uBITX from scratch and I noticed that in the schematic for the BAT54SL, Farhan has shown the component as having the cathode at pin 1 and anode at pin 2. However, the ON Semiconductor datasheet for this component has the anode at pin 1 and cathode at pin 2. On the schematic, for example, the mixer between T4 and T3 has the diode arrows going around in a clockwise direction.

If the datasheet is correct and this is indeed the proper configuration for this component, then the schematic appears to be in error.

So my question: is the direction of the diode ring is significant? Is the clockwise direction essential for proper operation of this circuit--are the pin numbers incorrect--or can can I successfully wire up the transformer toroids to the pins of the diodes as shown in Farhan's schematic, forgetting about what's actually inside these tiny black boxes?

-Michael VE1LEB

[] []


Tim Gorman
 

The direction of the diodes don't really matter in this instance. They
act as switches which are alternately turned on and off by the clk0
signal being alternatively positive or negative.

I don't know if you keep a journal or not. I do. I keep notes as to
things like this in my journal which include how I actually wired the
component and the actual internal wiring of the component. Date the
page and initial it so you can look back later and see what you did.

tim ab0wr

On Sat, 31 Mar 2018 05:36:32 -0700
"Michael LeBlanc" <michaelleblanc1@me.com> wrote:

I'm building a uBITX from scratch and I noticed that in the schematic
for the BAT54SL, Farhan has shown the component as having the cathode
at pin 1 and anode at pin 2. However, the ON Semiconductor datasheet
for this component has the anode at pin 1 and cathode at pin 2. On
the schematic, for example, the mixer between T4 and T3 has the diode
arrows going around in a clockwise direction.

If the datasheet is correct and this is indeed the proper
configuration for this component, then the schematic appears to be in
error. 

So my question: is the direction of the diode ring is significant? Is
the clockwise direction essential for proper operation of this
circuit--are the pin numbers incorrect--or can can I successfully
wire up the transformer toroids to the pins of the diodes as shown in
Farhan's schematic, forgetting about what's actually inside these
tiny black boxes?

-Michael VE1LEB


Paul Galburt - K2AYZ
 

If you really want to know, test the part with an multi-meter on the "diode" setting. That will resolve the polarity for sure.


Michael LeBlanc
 

Thanks Tim and Raj. I'll go ahead and wire things up now that I know. Once I get the mixer soldered-up, I'll check it with my signal generator and scope.

By the way, I do keep a journal: I scan most of my pencil sketches and drawings and save them in Evernote. I'm using SMD components; my layout drawings are made with Adobe Illustrator and hand-cutting pads and traces on a PCB using an engraver's burin acquired many years ago through my fine art degree. "Come up and see my etchings!" ;-) I hope to document this process once I get a little further along.

At any rate, this technique is very time-consuming at the front-end of the development cycle. It requires several layers of error-checking, and if I do it properly, it results in a perfectly-working circuit at initial power-up. 

-Michael VE1LEB


Tim Gorman
 

Michael,

I got used to using a prototype board called a Surfboard. There are
many different arrangements of pads. While expensive on a per-unit
basis it works for me. You still have to cut traces to make pads for
things like smd transistors and jfets and to provide isolated pads for
components but you don't have to do it for the whole circuit board. I
just layout how I'm going to do it on a piece of paper and then work on
the board.

I have never heard of a burin. I've always just used a hobby knife and
while it works its hard to get straight cuts and to then clean out
between the cuts.

What brand of burin do you use? Do they make one that would useful to
remove the trace between cuts?

I see this set on ebay, would they work?
www.ebay.com/itm/6pcs-2-35mm-Engraving-Bit-Burin-Graver-Pit-Olive-Ivory-Carving-Tool/173093922415?epid=8015978400&hash=item284d33a66f:g:IRcAAOSw-JJaWOOx

We are probably a little different in age. I keep my notes in engineers
notebooks, the kind that have graph paper on every page. A carryover
from my Chemistry/Physics/EE training in the late 60's and early 70's.
I like flipping through the pages.

Good luck in whatever you create!

tim ab0wr



On Mon, 02 Apr 2018 08:08:07 -0700
"Michael LeBlanc" <michaelleblanc1@me.com> wrote:

Thanks Tim and Raj. I'll go ahead and wire things up now that I know.
Once I get the mixer soldered-up, I'll check it with my signal
generator and scope.

By the way, I do keep a journal: I scan most of my pencil sketches
and drawings and save them in Evernote ( https://evernote.com/ ). I'm
using SMD components; my layout drawings are made with Adobe
Illustrator and hand-cutting pads and traces on a PCB using an
engraver's burin ( https://en.wikipedia.org/wiki/Burin_(engraving)
) acquired many years ago through my fine art degree. "Come up and
see my etchings!" ;-) I hope to document this process once I get a
little further along.

At any rate, this technique is very time-consuming at the front-end
of the development cycle. It requires several layers of
error-checking, and if I do it properly, it results in a
perfectly-working circuit at initial power-up. 

-Michael VE1LEB


Michael Hagen
 

I made some Mixer PCBs to play with.

I used an little more expensive match diode ring.

The is a spot for matching transformers and a Pad Attenuator.

I did use one and I heard signals, but did no testing.


Here is the data.

I have extra PCBs, email me for info?


Mike, WA6ISP

motdog at Verizon dot net





On 4/2/2018 9:38 AM, Tim Gorman wrote:
Michael,

I got used to using a prototype board called a Surfboard. There are
many different arrangements of pads. While expensive on a per-unit
basis it works for me. You still have to cut traces to make pads for
things like smd transistors and jfets and to provide isolated pads for
components but you don't have to do it for the whole circuit board. I
just layout how I'm going to do it on a piece of paper and then work on
the board. 

I have never heard of a burin. I've always just used a hobby knife and
while it works its hard to get straight cuts and to then clean out
between the cuts. 

What brand of burin do you use? Do they make one that would useful to
remove the trace between cuts?

I see this set on ebay, would they work?
www.ebay.com/itm/6pcs-2-35mm-Engraving-Bit-Burin-Graver-Pit-Olive-Ivory-Carving-Tool/173093922415?epid=8015978400&hash=item284d33a66f:g:IRcAAOSw-JJaWOOx

We are probably a little different in age. I keep my notes in engineers
notebooks, the kind that have graph paper on every page. A carryover
from my Chemistry/Physics/EE training in the late 60's and early 70's.
I like flipping through the pages. 

Good luck in whatever you create!

tim ab0wr



On Mon, 02 Apr 2018 08:08:07 -0700
"Michael LeBlanc" <michaelleblanc1@...> wrote:

Thanks Tim and Raj. I'll go ahead and wire things up now that I know.
Once I get the mixer soldered-up, I'll check it with my signal
generator and scope.

By the way, I do keep a journal: I scan most of my pencil sketches
and drawings and save them in Evernote ( https://evernote.com/ ). I'm
using SMD components; my layout drawings are made with Adobe
Illustrator and hand-cutting pads and traces on a PCB using an
engraver's burin ( https://en.wikipedia.org/wiki/Burin_(engraving)
) acquired many years ago through my fine art degree. "Come up and
see my etchings!" ;-) I hope to document this process once I get a
little further along.

At any rate, this technique is very time-consuming at the front-end
of the development cycle. It requires several layers of
error-checking, and if I do it properly, it results in a
perfectly-working circuit at initial power-up. 

-Michael VE1LEB





-- 
Mike Hagen, WA6ISP
10917 Bryant Street
Yucaipa, Ca. 92399
(909) 918-0058
PayPal ID  "MotDog@..."
Mike@...


Michael LeBlanc
 

On Mon, Apr 2, 2018 at 09:38 am, Tim Gorman wrote:
www.ebay.com/itm/6pcs-2-35mm-Engraving-Bit-Burin-Graver-Pit-Olive-Ivory-Carving-Tool/173093922415?epid=8015978400&hash=item284d33a66f:g:IRcAAOSw-JJaWOOx
I would call this a scribe or a grinder. The point of a burin pushes a "v" of copper away from the surface--it literally lifts the copper out of the groove. There's an interesting video at https://youtu.be/MRFq5Y74TwY (fast forward to just before 5:00 mark) that shows how an image is engraved on a copper plate using a burin. Old, old, very old technology! The ivory carving tools look like diamond-coated rotary grinders. For removing small amounts of PCB, I've used inexpensive diamond-tipped battery operated scribers that I think I picked up at my local dollar store.


Mike
 

Not to confuse things, but the BAT54 comes in several different pin configurations:


MVS Sarma
 

you need to select BAT54S  the one with suffixx "S"  it is two diodes in series.
 two such wired peoperly work as ring modulator. All the best
regards
sarma
 vu3zmv

Regards
MVS Sarma
 

On Thu, Apr 5, 2018 at 3:02 PM, Mike <msmith@...> wrote:
Not to confuse things, but the BAT54 comes in several different pin configurations: