Connect 'Source' signal name to 'GND'

Am 09.04.2018 um 14:25 schrieb dave hofer:

 

Hello,

I need to attach the 'Source' on the this diode to GND without changing its name but Eagle will not allow me to do so.  I've found older threads that mention creating a 'short' type part to do this.

But, I am wondering if this is made easier with newer version of Eagle?  I'm a maker who has managed to create 2 PCB with Eagle that actually work, but still consider myself an extreme newbie.

Any guidance would be greatly appreciated.

 

Dave

 

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Hi,

you want to connect the "anode" to GND?

You have to do it in schmeatic.

If you want to connect to the Copper-plate(polygone) you have to

name the Polygone as GND.

But in your pic there is a net connected to the anode. What is the name

of this?

GND? N$xx?

Werner

Werner,

I've added a bit more detail from my board layout.  Pin 9 is from an arduino pro mini (for reference) and all I am doing here is trigger a MOSFET.  Since the device being turned on/off via the MOSFET could have an electric motor, I added the Diode to reduce the power feedback when the motor stopped.  Without the diode, my arduino was resetting each time the motor was powered down (pin 9 pulled low).  I also discovered that this would not work unless I also connected the anode side of the diode to ground.

I do have a ground plane defined and it is named GND.

The signal name for the Anode is 'SOURCE' and it's net class is '0 default.'

I had a few of these built by Seeed Studio and they work fine when I solder a jumper wire from the Anode of the Diode to the GND pin of the pull down resistor.  My challenge is replacing that jumper wire with GND connection to the anode of the diode.

On 09/04/18 16:01, dave hofer wrote:

Werner,

 

I've added a bit more detail from my board layout.  Pin 9 is from an arduino pro mini (for reference) and all I am doing here is trigger a MOSFET.  Since the device being turned on/off via the MOSFET could have an electric motor, I added the Diode to reduce the power feedback when the motor stopped.  Without the diode, my arduino was resetting each time the motor was powered down (pin 9 pulled low).  I also discovered that this would not work unless I also connected the anode side of the diode to ground.

 

I do have a ground plane defined and it is named GND.

 

The signal name for the Anode is 'SOURCE' and it's net class is '0 default.'

 

I had a few of these built by Seeed Studio and they work fine when I solder a jumper wire from the Anode of the Diode to the GND pin of the pull down resistor.  My challenge is replacing that jumper wire with GND connection to the anode of the diode.

 

It would help if you could post the relevant part of your schematic and

a note of your intended motor wiring. Based purely on what you have

shown, the circuit doesn't appear to make sense. It looks like you've

provided a connector to wire the motor across the FET, which won't work.

Driving a DC motor (or other highly inductive load) is a very common

task and there is a standard circuit for doing it. That circuit does

include both a FET and a diode but not wired how you have.

And as to the original question... if the net connected to the anode of

the diode (and the source of the FET) is connected to ground then IT IS

GND and you should let Eagle call it GND.

Cheers,

Rob

On 09/04/18 16:01, dave hofer wrote:

Werner,

 

I've added a bit more detail from my board layout.  Pin 9 is from an arduino pro mini (for reference) and all I am doing here is trigger a MOSFET.  Since the device being turned on/off via the MOSFET could have an electric motor, I added the Diode to reduce the power feedback when the motor stopped.  Without the diode, my arduino was resetting each time the motor was powered down (pin 9 pulled low).  I also discovered that this would not work unless I also connected the anode side of the diode to ground.

 

I do have a ground plane defined and it is named GND.

 

The signal name for the Anode is 'SOURCE' and it's net class is '0 default.'

 

I had a few of these built by Seeed Studio and they work fine when I solder a jumper wire from the Anode of the Diode to the GND pin of the pull down resistor.  My challenge is replacing that jumper wire with GND connection to the anode of the diode.

 

It would help if you could post the relevant part of your schematic and

a note of your intended motor wiring. Based purely on what you have

shown, the circuit doesn't appear to make sense. It looks like you've

provided a connector to wire the motor across the FET, which won't work.

Driving a DC motor (or other highly inductive load) is a very common

task and there is a standard circuit for doing it. That circuit does

include both a FET and a diode but not wired how you have.

And as to the original question... if the net connected to the anode of

the diode (and the source of the FET) is connected to ground then IT IS

GND and you should let Eagle call it GND.

Cheers,

Rob

Rob,

Maybe this will help clarify. I am simply breaking the ground on the DC motor that has its own power supply. When I add the GND shown in White, the circuit works exactly as I intend it too.  When I set pin 9 to High, the motor turns on, when I set pin 9 to low the motor turns off.  It seems that maybe I should rename the 'Source' pin on the MOSFET and the source pin on the DIODE to GND.  Do you think that will work or do you still have concerns over this design?  I am new to the EAGLE world but as I've mentioned have had some success (maybe it's purely accidental) with my designs working.

I am attempting to implement a circuit like this one:  But it looks like I should connect both the Source and the Drain to Ground.  The image below was sourced from Electronics Hub. 

On 04/09/2018 04:01 PM, dave hofer wrote:

Rob,

 

Maybe this will help clarify. I am simply breaking the ground on the DC motor that has its own power supply. When I add the GND shown in White, the circuit works exactly as I intend it too.  When I set pin 9 to High, the motor turns on, when I set pin 9 to low the motor turns off.  It seems that maybe I should rename the 'Source' pin on the MOSFET and the source pin on the DIODE to GND.  Do you think that will work or do you still have concerns over this design?  I am new to the EAGLE world but as I've mentioned have had some success (maybe it's purely accidental) with my designs working.

 

 

I am attempting to implement a circuit like this one:  But it looks like I should connect both the Source and the Drain to Ground.  The image below was sourced from Electronics Hub.

 

 

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It seems you have some confusion on the FET pin names.

It is a 3 terminal device. Gate, Drain and source.

Tab is normally connected to the middle pin.

Paul

On 04/09/2018 04:01 PM, dave hofer wrote:

Rob,

 

Maybe this will help clarify. I am simply breaking the ground on the DC motor that has its own power supply. When I add the GND shown in White, the circuit works exactly as I intend it too.  When I set pin 9 to High, the motor turns on, when I set pin 9 to low the motor turns off.  It seems that maybe I should rename the 'Source' pin on the MOSFET and the source pin on the DIODE to GND.  Do you think that will work or do you still have concerns over this design?  I am new to the EAGLE world but as I've mentioned have had some success (maybe it's purely accidental) with my designs working.

 

 

I am attempting to implement a circuit like this one:  But it looks like I should connect both the Source and the Drain to Ground.  The image below was sourced from Electronics Hub.

 

 

--

To view any images and attachments in this post, visit:

https://www.element14.com/community/message/238181

 

It seems you have some confusion on the FET pin names.

It is a 3 terminal device. Gate, Drain and source.

Tab is normally connected to the middle pin.

Paul

Seriously Paul?  I am a newb but not at all confused about the FET pin names.  Did you look at the PCB.  They are all labeled properly.  Have no idea what the term 'Tab' that you use to refer means.

On 10/04/2018 12:25 a.m., dave hofer wrote:

 

Hello,

I need to attach the 'Source' on the this diode to GND without changing its name but Eagle will not allow me to do so.  I've found older threads that mention creating a 'short' type part to do this.

But, I am wondering if this is made easier with newer version of Eagle?  I'm a maker who has managed to create 2 PCB with Eagle that actually work, but still consider myself an extreme newbie.

Any guidance would be greatly appreciated.

 

Dave

 

--

To view any images and attachments in this post, visit:

https://www.element14.com/community/message/238103

 

Hi Paul

A few observations.

If you wish to emulate the layout of the Electronics Hub circuit, then

you have not achieved that.

(1)  You do not have a common point where the motor, diode and battery

are connected together as there is in the Electronics Hub circuit.

(2) Your image showing a motor and BAT1 3.7v has a problem. The diode is

forward biased all the time so even if you remove the MOSFET, current

will flow in the motor.

(3) If you review the data sheet of the MOSFET you will see it has an

internal diode that is in parallel with your discrete diode and oriented

the same way so it would be doing a similar job. You could remove your

discrete diode and still have the same circuit.

As per the Electronics Hub circuit the diode needs to be across the

motor and only the motor.

So to keep the same board layout you would have to do the following.

(a) remove the diode from the board as it is across the FET and it

should be across the motor

(b) Swap the wires going to J1 so the negative of the motor supply is on

the round pad on the right and the motor negative is on the left square pad.

(c) Mount the diode directly across the motor terminals with the anode

to the negative terminal

Also you need to achieve the equivalent of your white ground wire.

What you need to do is common the negative of the motor supply with the

ground of your arduino circuit.

Assuming you have a schematic, change the name of the net attached to J1

pin 2 to GND. That will make the connection. This assumes your pull down

resistor is connecting to a ground polygon in the area  and that polygon

encloses the pads currently connecting to the 'source' net which you

have just renamed GND.

HTH

Warren

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On 10/04/2018 12:25 a.m., dave hofer wrote:

 

Hello,

I need to attach the 'Source' on the this diode to GND without changing its name but Eagle will not allow me to do so.  I've found older threads that mention creating a 'short' type part to do this.

But, I am wondering if this is made easier with newer version of Eagle?  I'm a maker who has managed to create 2 PCB with Eagle that actually work, but still consider myself an extreme newbie.

Any guidance would be greatly appreciated.

 

Dave

 

--

To view any images and attachments in this post, visit:

https://www.element14.com/community/message/238103

 

Hi Paul

A few observations.

If you wish to emulate the layout of the Electronics Hub circuit, then

you have not achieved that.

(1)  You do not have a common point where the motor, diode and battery

are connected together as there is in the Electronics Hub circuit.

(2) Your image showing a motor and BAT1 3.7v has a problem. The diode is

forward biased all the time so even if you remove the MOSFET, current

will flow in the motor.

(3) If you review the data sheet of the MOSFET you will see it has an

internal diode that is in parallel with your discrete diode and oriented

the same way so it would be doing a similar job. You could remove your

discrete diode and still have the same circuit.

As per the Electronics Hub circuit the diode needs to be across the

motor and only the motor.

So to keep the same board layout you would have to do the following.

(a) remove the diode from the board as it is across the FET and it

should be across the motor

(b) Swap the wires going to J1 so the negative of the motor supply is on

the round pad on the right and the motor negative is on the left square pad.

(c) Mount the diode directly across the motor terminals with the anode

to the negative terminal

Also you need to achieve the equivalent of your white ground wire.

What you need to do is common the negative of the motor supply with the

ground of your arduino circuit.

Assuming you have a schematic, change the name of the net attached to J1

pin 2 to GND. That will make the connection. This assumes your pull down

resistor is connecting to a ground polygon in the area  and that polygon

encloses the pads currently connecting to the 'source' net which you

have just renamed GND.

HTH

Warren

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