### Author Topic: conventional vs electron flow - \$50 robot board  (Read 2126 times)

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#### ErikY

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##### conventional vs electron flow - \$50 robot board
« on: August 13, 2012, 06:31:41 AM »
I have been trying to learn as much electronics as possible while also learning robotics.

I read about something today that really threw me off.

The concept of electron flow vs. conventional circuit notation.

So it seems that electrons actually flow from negative to positive in a battery through a circuit, not the other way around, as conventional circuit notation shows.

So this is fine, I can adjust to this.

What really is throwing me off however is now that I am going back and studying my \$50 robot board, which is working well, and has been the basis for a lot of my tinkering lately.

So I ended up using webbot's version which uses a 9V running through a 5V voltage regulator to power the mcu, and a 6V unregulated source to power the servo's.

OK, so I am fine with that, all makes great sense, and I actually like this because if I need to run something more powerful, say 12 volts, I can leave in the 9V through the regulator, and power my mcu, and I can hopefully replace the 6V with a more powerful source for whatever I want to power like a linear actuator.

So here is where I am getting messed up.

We end up feeding the ground from the 6V battery through a .1uF capacitor, and into the gnd of the mcu, which ultimately connects to the other side of the mcu gnu, and ties into the ground from the 9V battery.

So, if I interpret electron flow literally, it would seem that we are sending electrons from the 6V right to the electrons of the 9V battery, which does not make sense, and even worse, we are sending to much pressure through the mcu.

So, it clearly appears to me that electrons are actually flowing from the + side of the battery, and not the - side of the battery.

Can someone help me to rectify this, and help me understand what I am missing?

Thanks!
« Last Edit: August 13, 2012, 11:14:15 AM by ErikY »

#### billhowl

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##### Re: conventional vs electron flow - \$50 robot board
« Reply #1 on: August 14, 2012, 06:37:24 AM »
Be it electron flow or conventional circuit notation, current only follow when the circuit are close.
electrons from the 6V will only follow though servo to the positive side of the 6V battery and will not follow to 9V as the circuit was not close( complete circuit), like wise for the 9V circuit.

#### ErikY

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##### Re: conventional vs electron flow - \$50 robot board
« Reply #2 on: August 15, 2012, 03:31:45 AM »
Thanks Bill,

That makes sense.

I am still a bit confused when it comes to the voltage regulator though. I can assume the voltage regulator is sending out electrons to the sensor inputs power bus, and the 6V battery pack is sending it's negative, or ground to the sensor bus as well, so if electrons really flow from the negative side of the battery to the positive side of the battery, we would have 2 busses on the sensor side getting electrons.

Is this really the case where the electrons flow negative to positive and not the other way around?

#### Gertlex

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##### Re: conventional vs electron flow - \$50 robot board
« Reply #3 on: August 15, 2012, 08:14:48 AM »
I wasn't able to visualize what you're describing.

So it seems that electrons actually flow from negative to positive in a battery through a circuit, not the other way around, as conventional circuit notation shows.

So this is fine, I can adjust to this.

Bold part is your problem   You don't need to to adjust anything; just ignore the concept of electrons when dealing with circuits.
I

#### ErikY

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##### Re: conventional vs electron flow - \$50 robot board
« Reply #4 on: August 15, 2012, 08:27:56 AM »
I wasn't able to visualize what you're describing.

So it seems that electrons actually flow from negative to positive in a battery through a circuit, not the other way around, as conventional circuit notation shows.

So this is fine, I can adjust to this.

Bold part is your problem   You don't need to to adjust anything; just ignore the concept of electrons when dealing with circuits.

You are right!

Everything was fine until I got to that part of what I was reading, really threw me for a loop!

#### waltr

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##### Re: conventional vs electron flow - \$50 robot board
« Reply #5 on: August 15, 2012, 05:54:14 PM »
As Gertlex said...

The direction flow of electrons is only important when dealing the the Physics of electronic devices, Vacuum tubes and semiconductors.

For circuits the directional flow of electrons doesn't matter,. What matters is a consistent notation of positive and negative. The other very important info, Stated by billhowl is "current only flows when the circuit is closed". This means there must be a path between the pos and neg terminals of a voltage (current) source. And there can be multiple 'paths' for the current to flow. examine the simple circuit of two resistors in parallel and across a battery.

By the way, The + and - notation came from Ben Franklin in the 1700's, long before anyone know electrons existed.