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Looking for a simple current sensing circuit...
is this one ok? http://mywebpages.comcast.net/khartnett232402/circuit.htm
or is there better ones?
Hi there,Much more info required. Give us a complete explination of what is
involved
e.g. do you want to detect current flowing in a wire, and if so, what is
the
'normal' flow? 240v AC, 9v DC, a few microamps from a phono stylus, what?
Without a complete explination (hint: write at least two paragraphs) we
can't help you.
"Bill T" <bill24@optusnet.com.au> wrote in message
news:43403159$1@news1.veridas.net...
Looking for a simple current sensing circuit...
is this one ok? http://mywebpages.comcast.net/khartnett232402/circuit.htm
or is there better ones?
The above circuit is a comparator that tells you when a certain"Craig Hart" <news@news.com> wrote in message
news:Ce20f.5623$U51.2249@news-server.bigpond.net.au...
Much more info required. Give us a complete explination of what is
involved
e.g. do you want to detect current flowing in a wire, and if so, what is
the
'normal' flow? 240v AC, 9v DC, a few microamps from a phono stylus, what?
Without a complete explination (hint: write at least two paragraphs) we
can't help you.
"Bill T" <bill24@optusnet.com.au> wrote in message
news:43403159$1@news1.veridas.net...
Looking for a simple current sensing circuit...
is this one ok? http://mywebpages.comcast.net/khartnett232402/circuit.htm
or is there better ones?
Hi there,
thanks in advance, I haven't really worked out what current is
going to be flowing yet, but at the moment I'm estimating 12V DC at 40-50W,
but yeah, it'll be monitor current through a wire, in this instance may be
the 12VDC supply line, let me know if you find anything! Thanks!
that'll be all over the place with transistor (expect a 4:1 betaOn Mon, 3 Oct 2005 14:31:56 +1000, "Bill T" <bill24@optusnet.com.au
put finger to keyboard and composed:
"Craig Hart" <news@news.com> wrote in message
news:Ce20f.5623$U51.2249@news-server.bigpond.net.au...
Much more info required. Give us a complete explination of what is
involved
e.g. do you want to detect current flowing in a wire, and if so, what is
the
'normal' flow? 240v AC, 9v DC, a few microamps from a phono stylus, what?
Without a complete explination (hint: write at least two paragraphs) we
can't help you.
"Bill T" <bill24@optusnet.com.au> wrote in message
news:43403159$1@news1.veridas.net...
Looking for a simple current sensing circuit...
is this one ok? http://mywebpages.comcast.net/khartnett232402/circuit.htm
or is there better ones?
Hi there,
thanks in advance, I haven't really worked out what current is
going to be flowing yet, but at the moment I'm estimating 12V DC at 40-50W,
but yeah, it'll be monitor current through a wire, in this instance may be
the 12VDC supply line, let me know if you find anything! Thanks!
The above circuit is a comparator that tells you when a certain
current threshold has been exceeded. Is that all you need, or do you
want a readout of the actual current?
If the former, then a simple circuit such as the following may
suffice:
PNP transistor
E C
+V o--|---\___/-----> to overload indicator
| |
| R
| |
|-Rs--|------> to load
Note that you will lose up to 0.6V across sense resistor Rs. If the
max current is to be 5A, then choose Rs = 0.12 ohm, 5W+.
-- Franc Zabkar
Please remove one 'i' from my address when replying by email.
Franc Zabkar wrote:
If the former, then a simple circuit such as the following may
suffice:
PNP transistor
E C
+V o--|---\___/-----> to overload indicator
| |
| R
| |
|-Rs--|------> to load
Note that you will lose up to 0.6V across sense resistor Rs. If the
max current is to be 5A, then choose Rs = 0.12 ohm, 5W+.
that'll be all over the place with transistor (expect a 4:1 beta variation
from a single manufacturer), temperature and no doubt sock colour.
depends on the load really. If you want an astonishingly crude circuit,"Terry Given"
Franc Zabkar wrote:
If the former, then a simple circuit such as the following may
suffice:
PNP transistor
E C
+V o--|---\___/-----> to overload indicator
| |
| R
| |
|-Rs--|------> to load
Note that you will lose up to 0.6V across sense resistor Rs. If the
max current is to be 5A, then choose Rs = 0.12 ohm, 5W+.
that'll be all over the place with transistor (expect a 4:1 beta variation
from a single manufacturer), temperature and no doubt sock colour.
** Individual transistor beta will have no effect, the circuit operates on
device Vbe - you arrogant sheep shagger.
Nah, barefoot.Temperature will increase the sensitivity by 2mV ( or 16mA in this case )
per degree C - likely a trivial amount.
Bet *YOU* have socks of different colours as sizes on each foot.
I thought your RMS current meter was pretty good, Phil. Its not quite........ Phil
Phil Allison wrote:
Franc Zabkar wrote:
If the former, then a simple circuit such as the following may
suffice:
PNP transistor
E C
+V o--|---\___/-----> to overload indicator
| |
| R
| |
|-Rs--|------> to load
Note that you will lose up to 0.6V across sense resistor Rs. If the
max current is to be 5A, then choose Rs = 0.12 ohm, 5W+.
that'll be all over the place with transistor (expect a 4:1 beta
variation from a single manufacturer), temperature and no doubt sock
colour.
** Individual transistor beta will have no effect, the circuit operates
on device Vbe - you arrogant sheep shagger.
depends on the load really.
If you want an astonishingly crude circuit, then use this one. Beta does
count, because the current flowing into the "sensing circuit" is one
beta'th of the load current.
... say you use a grounded resistor, and a comparator. Then the actual trip
point will depend strongly on Beta.
Temperature will increase the sensitivity by 2mV ( or 16mA in this case )
per degree C - likely a trivial amount.
Bet *YOU* have socks of different colours as sizes on each foot.
Nah, barefoot.
I thought your RMS current meter was pretty good, Phil.
With respect, I think you are having a brain fart. The circuit will doFranc Zabkar wrote:
"Bill T" <bill24@optusnet.com.au> wrote in message
news:43403159$1@news1.veridas.net...
Looking for a simple current sensing circuit...
is this one ok? http://mywebpages.comcast.net/khartnett232402/circuit.htm
or is there better ones?
I haven't really worked out what current is
going to be flowing yet, but at the moment I'm estimating 12V DC at 40-50W,
but yeah, it'll be monitor current through a wire, in this instance may be
the 12VDC supply line, let me know if you find anything! Thanks!
The above circuit is a comparator that tells you when a certain
current threshold has been exceeded. Is that all you need, or do you
want a readout of the actual current?
If the former, then a simple circuit such as the following may
suffice:
PNP transistor
E C
+V o--|---\___/-----> to overload indicator
| |
| R
| |
|-Rs--|------> to load
Note that you will lose up to 0.6V across sense resistor Rs. If the
max current is to be 5A, then choose Rs = 0.12 ohm, 5W+.
that'll be all over the place with transistor (expect a 4:1 beta
variation from a single manufacturer), temperature and no doubt sock colour.
"Terry Given"
Phil Allison wrote:
Franc Zabkar wrote:
If the former, then a simple circuit such as the following may
suffice:
PNP transistor
E C
+V o--|---\___/-----> to overload indicator
| |
| R
| |
|-Rs--|------> to load
Note that you will lose up to 0.6V across sense resistor Rs. If the
max current is to be 5A, then choose Rs = 0.12 ohm, 5W+.
that'll be all over the place with transistor (expect a 4:1 beta
variation from a single manufacturer), temperature and no doubt sock
colour.
** Individual transistor beta will have no effect, the circuit operates
on device Vbe - you arrogant sheep shagger.
depends on the load really.
** Bullshit - you are a pathetic loser.
If you want an astonishingly crude circuit, then use this one. Beta does
count, because the current flowing into the "sensing circuit" is one
beta'th of the load current.
** Really desperate sheep shagger crapology.
... say you use a grounded resistor, and a comparator. Then the actual
trip point will depend strongly on Beta.
** What **** utter **** bullshit.
Temperature will increase the sensitivity by 2mV ( or 16mA in this
case ) per degree C - likely a trivial amount.
Bet *YOU* have socks of different colours as sizes on each foot.
Nah, barefoot.
** Wot about the gumboots you shove the ewe's hind legs into ?
I thought your RMS current meter was pretty good, Phil.
** Can I expect to see your clones on the NZ market soon ??
........... Phil