WEBVTT
Kind: captions
Language: en

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♪ ...Just look at what the current brings;
So high, it's only promising... ♪

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Hello.

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Today we're demonstrating

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a 40 amp over-trace 
GMR current sensor.

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We'll use a section of a new demo board
you can buy on our Website.

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The sensor detects 
the magnetic field

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generated by the current
running through the trace.

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The heavy-duty trace is 
a half-inch wide 
and uses two-ounce copper.

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It can carry 40 amps with 
a 30 degree C temperature rise.

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40 amps is also 
approximately the current

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that saturates the sensor
in this configuration.

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An oscilloscope displays 
the sensor output vs. current.

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A shunt resistor allows us
to measure the actual current.

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Let's head to the lab.

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Here's the demo board.

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We're powering the sensor 
with a nine-volt battery,

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but you can use any supply 
between one and 12 volts.

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We've done other demos for 
sensing several amps,

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but this is heavier-duty.

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A big power supply
in current mode drives the trace.

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A one milliohm shunt

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on the X-axis of the 'scope
shows the trace current,

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which works out to 
10 amps per division,

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and the sensor output 
is on the Y-axis.

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We'll sweep the current,

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and you can see 
the sensor is accurate

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with negligible hysteresis.

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So the "Lab Results" are in.

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We've shown that 
GMR sensors can measure

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at least 40 amps on circuit boards

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with no resistive losses.

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GMR sensors have large signals,

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and they're inherently isolated.

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You can order parts 
or demo boards online,

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and we have a handy Web app
for current-sensing calculations.