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• It s come to my attention that there is a particular type of diode called a varicap diode, which acts as a capacitor in reverse bias, and the capacitance is
Message 1 of 7 , Jun 29, 2012
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It's come to my attention that there is a particular type of diode called a varicap diode, which acts as a capacitor in reverse bias, and the capacitance is controlled by the voltage at the anode, hence the name. It's also come to my attention that these are considerably easy to attain. I recently pulled three out of a DVD player and didn't even know it. What I had in mind was to construct a neuron consisting of an inverter(duh), a resistor(again, duh), a varicap(d... wait, wuh?), and three more resistors. While the resistor is tied to ground, it's also tied between the two other resistors in a voltage divider setup, as well as an extra, higher value resistor between the inverter input and the Nv input.

Whereas a regular neuron with fixed resistor/capacitor values will change behavior when supply voltage varies, namely, a solar powered walker will move slower as the storage cap empties, only in part because voltage goes down, but more importantly because the ratio between component values to Vcc value increases, causing each Nv to have a longer delay. Now this isn't necessarily the case because any type 1 or 2 solar engine cuts power before it gets that low, but wouldn't you love for the robot to use all of the stored charge in the cap, rather than a fraction of it, not only making it more efficient, but also longer lived per charge? A type 3 solar engine accomplishes this, but the voltage dissipates as the cap empties. So to make a control circuit that maintains the same time constants even near "death", or during a power spike, I want to implement the aforementioned circuit.

At normal Vcc, the resistor and varicap assume normal values for proper timing. The resistor actually assumes half of it's marked resistance during an active process, because the voltage divider decreases the charge difference across the resistor's terminals. However, as the supply voltage drops, the charge across the resistor's terminals during an active process increases, so that it takes longer for the charge to drain. The fourth internal resistor should keep a fairly constant output voltage. Also, the internal charge of the neuron determines the capacitance of the varicap. As Vcc drops, the R1's resistance increases, causing a higher voltage to build up at R2, causing the varicap's capacitance to decrease during an active process. Or the opposite could happen if Vcc increases beyond normal parameters, but that's not an important characteristic for a solar application. Here's a diagram of this circuit:

>-----||<|----+--R2--|>o----->
|
R1
|
+-R3---+---R4->

If anyone likes this idea, then go ahead and do something with it. It's not necessarily designed for extra functionality, just to achieve higher efficiency and to make a more voltage flexible design.
Hope you enjoy,

Connor

• Hi Conner; ... All diodes do this. It s just the varicaps generally have large initial values of capacitance. ... Some ceramic capacitors exhibit this
Message 2 of 7 , Jun 29, 2012
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Hi Conner;

connor_ramsey@... wrote:

> It's come to my attention that there is a particular type of
> diode called a varicap diode, which acts as a capacitor in
> reverse bias, and the capacitance is controlled by the
> voltage at the anode, hence the name. It's also come to my
> attention that these are considerably easy to attain.
> I recently pulled three out of a DVD player and didn't even
> know it. What I had in mind was to construct a neuron
> consisting of an inverter(duh), a resistor(again, duh),
> a varicap(d... wait, wuh?), and three more resistors.
> While the resistor is tied to ground, it's also tied between
> the two other resistors in a voltage divider setup, as well
> as an extra, higher value resistor between the inverter
> input and the Nv input.

All diodes do this. It's just the varicaps generally have
large initial values of capacitance.

> Whereas a regular neuron with fixed resistor/capacitor
> values will change behavior when supply voltage varies,
> namely, a solar powered walker will move slower as the
> storage cap empties, only in part because voltage goes
> down, but more importantly because the ratio between
> component values to Vcc value increases, causing each
> Nv to have a longer delay. Now this isn't necessarily
> the case because any type 1 or 2 solar engine cuts power
> before it gets that low, but wouldn't you love for the
> robot to use all of the stored charge in the cap, rather
> than a fraction of it, not only making it more efficient,
> but also longer lived per charge? A type 3 solar engine
> accomplishes this, but the voltage dissipates as the cap
> empties. So to make a control circuit that maintains the
> same time constants even near "death", or during a power
> spike, I want to implement the aforementioned circuit.

> At normal Vcc, the resistor and varicap assume normal
> values for proper timing. The resistor actually assumes
> half of it's marked resistance during an active process,
> because the voltage divider decreases the charge difference
> across the resistor's terminals. However, as the supply
> voltage drops, the charge across the resistor's terminals
> during an active process increases, so that it takes longer
> for the charge to drain. The fourth internal resistor
> should keep a fairly constant output voltage. Also, the
> internal charge of the neuron determines the capacitance of
> the varicap. As Vcc drops, the R1's resistance increases,
> causing a higher voltage to build up at R2, causing the
> varicap's capacitance to decrease during an active process.
> Or the opposite could happen if Vcc increases beyond normal
> parameters, but that's not an important characteristic for
> a solar application. Here's a diagram of this circuit:

> >-----||<|----+--R2--|>o----->
> |
> R1
> |
> +-R3---+---R4->

> If anyone likes this idea, then go ahead and do something with
> it. It's not necessarily designed for extra functionality,
> just to achieve higher efficiency and to make a more voltage
> flexible design.
> Hope you enjoy,

Some ceramic capacitors exhibit this phenomena also. See:

> Connor

Duane

--
Home of the \$35 Solar Tracker Receiver
http://www.redrok.com/led3xassm.htm [*]
Thermonuclear Solar Energy from the Sun / |
Energy (the SUN) \ \ \ / / |
Red Rock Energy \ \ / / |
Duane C. Johnson Designer \ \ / \ / |
1825 Florence St Heliostat,Control,& Mounts |
White Bear Lake, Minnesota === \ / \ |
USA 55110-3364 === \ |
(651)426-4766 use Courier New Font \ |
redrok@... (my email: address) \ |
http://www.redrok.com (Web site) ===
• Hi Conner; Sory about that I entered the wromg link. ... All diodes do this. It s just the varicaps generally have large initial values of capacitance. ...
Message 3 of 7 , Jun 29, 2012
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Hi Conner;

connor_ramsey@... wrote:

> It's come to my attention that there is a particular type of
> diode called a varicap diode, which acts as a capacitor in
> reverse bias, and the capacitance is controlled by the
> voltage at the anode, hence the name. It's also come to my
> attention that these are considerably easy to attain.
> I recently pulled three out of a DVD player and didn't even
> know it. What I had in mind was to construct a neuron
> consisting of an inverter(duh), a resistor(again, duh),
> a varicap(d... wait, wuh?), and three more resistors.
> While the resistor is tied to ground, it's also tied between
> the two other resistors in a voltage divider setup, as well
> as an extra, higher value resistor between the inverter
> input and the Nv input.

All diodes do this. It's just the varicaps generally have
large initial values of capacitance.

> Whereas a regular neuron with fixed resistor/capacitor
> values will change behavior when supply voltage varies,
> namely, a solar powered walker will move slower as the
> storage cap empties, only in part because voltage goes
> down, but more importantly because the ratio between
> component values to Vcc value increases, causing each
> Nv to have a longer delay. Now this isn't necessarily
> the case because any type 1 or 2 solar engine cuts power
> before it gets that low, but wouldn't you love for the
> robot to use all of the stored charge in the cap, rather
> than a fraction of it, not only making it more efficient,
> but also longer lived per charge? A type 3 solar engine
> accomplishes this, but the voltage dissipates as the cap
> empties. So to make a control circuit that maintains the
> same time constants even near "death", or during a power
> spike, I want to implement the aforementioned circuit.

> At normal Vcc, the resistor and varicap assume normal
> values for proper timing. The resistor actually assumes
> half of it's marked resistance during an active process,
> because the voltage divider decreases the charge difference
> across the resistor's terminals. However, as the supply
> voltage drops, the charge across the resistor's terminals
> during an active process increases, so that it takes longer
> for the charge to drain. The fourth internal resistor
> should keep a fairly constant output voltage. Also, the
> internal charge of the neuron determines the capacitance of
> the varicap. As Vcc drops, the R1's resistance increases,
> causing a higher voltage to build up at R2, causing the
> varicap's capacitance to decrease during an active process.
> Or the opposite could happen if Vcc increases beyond normal
> parameters, but that's not an important characteristic for
> a solar application. Here's a diagram of this circuit:

> >-----||<|----+--R2--|>o----->
> |
> R1
> |
> +-R3---+---R4->

> If anyone likes this idea, then go ahead and do something with
> it. It's not necessarily designed for extra functionality,
> just to achieve higher efficiency and to make a more voltage
> flexible design.
> Hope you enjoy,

Some ceramic capacitors exhibit this phenomena also. See:
http://www.redrok.com/images/capvaractor.gif

> Connor

Duane

--
Home of the \$35 Solar Tracker Receiver
http://www.redrok.com/led3xassm.htm [*]
Thermonuclear Solar Energy from the Sun / |
Energy (the SUN) \ \ \ / / |
Red Rock Energy \ \ / / |
Duane C. Johnson Designer \ \ / \ / |
1825 Florence St Heliostat,Control,& Mounts |
White Bear Lake, Minnesota === \ / \ |
USA 55110-3364 === \ |
(651)426-4766 use Courier New Font \ |
redrok@... (my email: address) \ |
http://www.redrok.com (Web site) ===
• ... I am fully aware that all diodes do this, though only varicaps achieve this function reliably. The multilayer cap thing is new to me, and that will work
Message 4 of 7 , Jun 29, 2012
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> All diodes do this. It's just the varicaps generally have
> large initial values of capacitance.

> Some ceramic capacitors exhibit this phenomena also. See:
> http://www.redrok.com/images/capvaractor.gif

I am fully aware that all diodes do this, though only varicaps achieve this function reliably. The multilayer cap thing is new to me, and that will work too, but varicaps, at least the small ones, are likely cheaper then the caps, maybe around 10 cents or so. And they're found in everything with a volume control as well. So I'm just gonna stick with them for now.

And sorry but the link page you gave me was completely illegible. It might be just me, but it's worth looking into if you can. I'll just look the thing up.

Thanks!
• ... Hi. Don t take this the wrong way, but it REALLY bugs me when people spell my name wrong. Because it s my name. Don t get it wrong. Please. Connor, with an
Message 5 of 7 , Jun 29, 2012
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--- In beam@yahoogroups.com, "Duane C. Johnson" <redrok@...> wrote:
>
> Hi Conner;

Hi. Don't take this the wrong way, but it REALLY bugs me when people spell my name wrong. Because it's my name. Don't get it wrong. Please.

Connor, with an O.
• Will you use this on one of your bots?
Message 6 of 7 , Jul 1, 2012
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Will you use this on one of your bots?

--- In beam@yahoogroups.com, "connor_ramsey@..." <connor_ramsey@...> wrote:
>
> It's come to my attention that there is a particular type of diode
> called a varicap diode, which acts as a capacitor in reverse bias, and
> the capacitance is controlled by the voltage at the anode, hence the
> name. It's also come to my attention that these are considerably easy to
> attain. I recently pulled three out of a DVD player and didn't even know
> it. What I had in mind was to construct a neuron consisting of an
> inverter(duh), a resistor(again, duh), a varicap(d... wait, wuh?), and
> three more resistors. While the resistor is tied to ground, it's also
> tied between the two other resistors in a voltage divider setup, as well
> as an extra, higher value resistor between the inverter input and the Nv
> input.
>
> Whereas a regular neuron with fixed resistor/capacitor values will
> change behavior when supply voltage varies, namely, a solar powered
> walker will move slower as the storage cap empties, only in part because
> voltage goes down, but more importantly because the ratio between
> component values to Vcc value increases, causing each Nv to have a
> longer delay. Now this isn't necessarily the case because any type 1 or
> 2 solar engine cuts power before it gets that low, but wouldn't you love
> for the robot to use all of the stored charge in the cap, rather than a
> fraction of it, not only making it more efficient, but also longer lived
> per charge? A type 3 solar engine accomplishes this, but the voltage
> dissipates as the cap empties. So to make a control circuit that
> maintains the same time constants even near "death", or during a power
> spike, I want to implement the aforementioned circuit.
>
> At normal Vcc, the resistor and varicap assume normal values for proper
> timing. The resistor actually assumes half of it's marked resistance
> during an active process, because the voltage divider decreases the
> charge difference across the resistor's terminals. However, as the
> supply voltage drops, the charge across the resistor's terminals during
> an active process increases, so that it takes longer for the charge to
> drain. The fourth internal resistor should keep a fairly constant output
> voltage. Also, the internal charge of the neuron determines the
> capacitance of the varicap. As Vcc drops, the R1's resistance increases,
> causing a higher voltage to build up at R2, causing the varicap's
> capacitance to decrease during an active process. Or the opposite could
> happen if Vcc increases beyond normal parameters, but that's not an
> important characteristic for a solar application. Here's a diagram of
> this circuit:
>
>
>
>
> >-----||<|----+--R2--|>o----->
> |
> R1
> |
> +-R3---+---R4->
>
>
> If anyone likes this idea, then go ahead and do something with it. It's
> not necessarily designed for extra functionality, just to achieve higher
> efficiency and to make a more voltage flexible design.
> Hope you enjoy,
>
> Connor
>
• ... First solar walker I build will have these.
Message 7 of 7 , Jul 1, 2012
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--- In beam@yahoogroups.com, "Amit" <amitjones101@...> wrote:
>
> Will you use this on one of your bots?

First solar walker I build will have these.
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