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But everything to do with losses its iron core and the copperWhy does my 9v D.C. transformer only give a max. amps. of 0.22A?.
I've looked inside it and it doesnt seen to have any resistor in
series to restrict the current.
A 6v. battery charger can give out 4 amps.,which proves its nothing
to do with the voltage of input or output.
The output current has to pass through the resistance of the secondaryWhy does my 9v D.C. transformer only give a max. amps. of 0.22A?.
I've looked inside it and it doesnt seen to have any resistor in
series to restrict the current.
A 6v. battery charger can give out 4 amps.,which proves its nothing
to do with the voltage of input or output.
Thanks.
Why does my 9v D.C. transformer only give a max. amps. of 0.22A?.
I've looked inside it and it doesnt seen to have any resistor in
series to restrict the current.
A 6v. battery charger can give out 4 amps.,which proves its nothing
to do with the voltage of input or output.
Thanks.
Use your 15V wall wart and put a light bulb in series. Size the lightI have a cordless floor sweeper that's missing the wall wart power
supply it came with. Inside the sweeper there is a 7.2 volt nicad pack
with just a power resistor to limit current to the battery when
charging (very primitive). The resistor is something like an ohm, and
the size is a watt or two. I don't know what voltage the wall wart
was, but it was probably unregulated. The sticker on the sweeper says
that when new, and charging the (empty) battery for the first time, to
let it charge for 16 hours.
When experimenting I hook the sweeper up to wall warts that have 15 or
20 volts open circuit things get hot -- the resistor in the sweeper,
and the wall wart.
I have a 7808 8-volt regulator I could wire up to a 12 or 15 volt wall
wart. My question, is 8 volts enough for charging a 7.2 volt nicad
pack? A really slow charge is good, this thing will sit in the hall of
the building where I live and probably just stay on the charger all the
time. If 8 volts is too low, I can get whatever voltage I need by
putting a diode or diodes in the ground terminal of the regulator to
bump the voltage up, or use a voltage divider like on a 317... I'm
really asking what fixed voltage would be best, with a 1-ohm resistor
in series, to leave a 7.2 volt nicad pack on all the time and not
overheat; it's okay if it takes a whole day to charge.
Yes. The relay output is rated for 12 VDC, 10 A, and the current drawn byokay I have one more question about this led circuit. Can I use this
sound activated switch to hook up to my leds?
http://www.electronickits.com/kit/complete/elec/k126.htm
the circuit in fig1 works by feeding back the signal at the emiter to theI have electronics hobby and just start learning how oscillator works,
like the loop gain must be >= 1 and the phase between the input and
output should be 0 degree. The problem is, when I see the actual (even
simple) oscillation circuit, I am at a loss how it exactly works.
"http://img13.imagevenue.com/loc70/a2a_osc123.jpg"
For example, in Fig.1, what's the use of resistor R2, from oscillation
point of view (not from transistor DC basing point of view)? I figure
that, since C3 is basically to short AC (i.e. RF in this case), it
seems to be equivalent to place one end of the crystal directly to the
emitter, as shown in Fig.2. Unfortunately, it does not oscillate this
way. Likewise, since C3 is to short the AC, then it should also be OK
to remove R2 and C3 completely, and place the crystal in a way shown in
Fig.3. However, it does not oscillate, either.
(1) So what is the function of R2 here?
(2) If it is a must for the oscillator to work, how to choose it?
(3) How to choose the value of C3?
Your help is appreciated!
What are you gonna use it for?I was looking at some PC-Based Logic Analyzers. I came across this
one:
http://www.pctestinstruments.com/
Has anybody of you used it before. My requirement is fairly simple. I
have a 8-bit/16-Bit microcontroller at 12MHz. This one samples at 500
MHz. It has 34 channel. Seems a pretty good deal.
Any idea how good it works ?
An article by Jack Ganssle is on embedded.com that compares a fewI was looking at some PC-Based Logic Analyzers. I came across this
one:
http://www.pctestinstruments.com/
Has anybody of you used it before. My requirement is fairly simple. I
have a 8-bit/16-Bit microcontroller at 12MHz. This one samples at 500
MHz. It has 34 channel. Seems a pretty good deal.
Neil C.? GE32?mnitin73@gmail.com> wrote in message
news:1114481060.688099.87690@l41g2000cwc.googlegroups.com...
Can I connect the port to the rx pin of the 9 pin serial port and make
any sense? Are the 1553B interface cards standard or does it have to be
custom made depending on the equipment
Excalibur make 1553 interface cards but they are about Ł1500 each.
The data (as I recall, no doubt someone will correct/clarify...)
is a serial differential transformer coupled stream, at 1Megbaud.
Each data word is 16 bits, with a couple of start and stop bits.
The words are grouped in messages, and sent under control of the bus
controller.
You may have a controller or remote terminal (slave device).
The voltage level ranges from 3 to 30 volts.
Probably difficult to get a com port to talk/listen.
hope this helps,
Neil
If you force charge onto the gate of a MOSFET, you change the gate-sourceHello Everybody:
Good morning. I have a couple of basic MOSFET questions that I would
like to clarify. I have studied a lot of articles, asked a few people
about this doubt but could not find a satisfactory explanation. I am
hoping somebody will take the trouble of clarifying my doubt.
MOSFETs, as I understand, are voltage-controlled devices. Doesn't that
mean that they need a charge (voltage) applied to the gate to make the
device conducting? If this is the case, in some circuits I have found
in the process of learning analog VLSI, what is the meaning of a "gate
of a nmos/pmos transistor being driven by the output of a current
mirror?" I have read that the output current of the current mirror is
used to bias a next stage. What exactly does this mean?
Secondly, if the MOSFETs are voltage-controlled devices, why do we
most of the time deal with currents when talking about VLSI systems?
Hope, I am clear with my questions. Thanks in advance.
Regards,
Saran
Tell us more.I have a circuit that uses a light bulb as above and a LM317 voltage
regulator to limit charging current to 100ma and adjust the cutoff
voltage as required.
Richard
You can do that with lower differential voltage and lower voltage lightIt's a little unclear whether spudnuty used the 317 in the
constant-current config or in the usual voltage-regulating config and a
bulb in series with the output.
Mikes suggestion is the simplest but I want a setup where the charging
current drops off as the nicads voltage rises. That's why I was
thinking about using a comparatively low 8 or 9 volts, so that as the
batteries rising voltage approaches that, the voltage across the
current-limiting element (bulb or power resistor) will fall very low,
causing the charging current to diminish.
Temperature cutoff is the best way I know to cook the life out of nicads.the best way to charge nicads; it is more how you would charge
lead-acid batteries. Maybe I should tape a thermistor to the battery
and use that to turn off the charging.
---Yup... that's the plan for phase 1. Plan for phase 2 (assuming phase 1
ever works) is to add another sensor to determine if there is actually
a car (or movement?) in the garage. If there is no car (or if there is
movement) then the remote won't activate.
Charge and voltage are not the same thing. The gates of mosMOSFETs, as I understand, are voltage-controlled devices. Doesn't that
mean that they need a charge (voltage) applied to the gate to make the
device conducting?
A current mirror provides a controlled current that passes charge intoIf this is the case, in some circuits I have found
in the process of learning analog VLSI, what is the meaning of a "gate
of a nmos/pmos transistor being driven by the output of a current
mirror?"
It means that the gate voltage is changed at a controlled rate by theI have read that the output current of the current mirror is
used to bias a next stage. What exactly does this mean?
Secondly, if the MOSFETs are voltage-controlled devices, why do we most
of the time deal with currents when talking about VLSI systems?
(snip)
Yes.hartly wrote:
Why does my 9v D.C. transformer only give a max. amps. of 0.22A?.
I've looked inside it and it doesnt seen to have any resistor in
series to restrict the current.
A 6v. battery charger can give out 4 amps.,which proves its nothing
to do with the voltage of input or output.
Thanks.
size of the core, wire, etc...
the wire in the transformer is small, thus creating resistance of its own.
No, core saturation does not act to limit the load current.Core saturation
Yes.with inductance etc. etc. etc....
Why does my 9v D.C. transformer only give a max. amps. of 0.22A?.
I've looked inside it and it doesnt seen to have any resistor in
series to restrict the current.
A 6v. battery charger can give out 4 amps.,which proves its nothing
to do with the voltage of input or output.
Thanks.
size of the core, wire, etc...
In air or vacuum, for an infinitely long wire, the strengthHi,
Hello.
Can I calculate the magnetic field around a wire in inches, I have
voltage and current.
Also, the magnetic field around a wire is cylindrical.
Thanks, for helping.
Welcome.
That is the principle. For linear capacitors, the math isSo, let me restate what I understood. The current mirror's output
current is used to charge the gate of the transistor. So, depending on
the magnitude of the current, the gate voltage increaser faster or
slower (sorry about my layman language, I just want to be very very
clear).
Yes.If I understood this correctly, then:
1) If a current mirror is charging the gate of a transistor, or in
other words, changing its Vgs, the maximum Vgs value is determined by
the saturation voltage for the mirror.
You have restated what I said, so if you are wrong, we are both wrong.2) We are controlling the rate at which gate is charged in a circuit.
Have I understood this correctly? Thanks in advance.
Work (currently) for BAE Systems.neil wrote:
mnitin73@gmail.com> wrote in message
news:1114481060.688099.87690@l41g2000cwc.googlegroups.com...
Can I connect the port to the rx pin of the 9 pin serial port and make
any sense? Are the 1553B interface cards standard or does it have to be
custom made depending on the equipment
Excalibur make 1553 interface cards but they are about Ł1500 each.
The data (as I recall, no doubt someone will correct/clarify...)
is a serial differential transformer coupled stream, at 1Megbaud.
Each data word is 16 bits, with a couple of start and stop bits.
The words are grouped in messages, and sent under control of the bus
controller.
You may have a controller or remote terminal (slave device).
The voltage level ranges from 3 to 30 volts.
Probably difficult to get a com port to talk/listen.
hope this helps,
Neil
Neil C.? GE32?
I'm Neil from Chatham in Kent, England.
Yes. You are correct.So, let me restate what I understood. The current mirror's output
current is used to charge the gate of the transistor. So, depending on
the magnitude of the current, the gate voltage increaser faster or
slower (sorry about my layman language, I just want to be very very
clear).
If I understood this correctly, then:
1) If a current mirror is charging the gate of a transistor, or in
other words, changing its Vgs, the maximum Vgs value is determined by
the saturation voltage for the mirror.
2) We are controlling the rate at which gate is charged in a
circuit.
Have I understood this correctly? Thanks in advance.