Read: 660 times
|#113056 - 7805 and get 10mA and 100mA|
Responding to: Kai Klaas's previous message
0.010 Amps * 0.020 ohms = 0.0002 volts
.2 millivolts is kind of tiny A gain of like 200
watch for noise
from what you have said i got that, since the measured voltage would be too less(.2mV) for low CR, this voltage(.2mV) has to be safeguarded against noise issue.
If this is what you describe, what could i do to achieve it?
A careful PCB design (or) handling any design technique?
could you give me some knowledge of how to do that.
Kai Klaas said:
I dont have any idea about it Kai.
Could you give me some more info on 'how and where it would be developed in my circuit?
Kai Klass said:
Why not using a simple 1k5 resistor for the 10mA constant current and a 150R resistor for the 100mA constant current, both in combination with +15V voltage source? Even with a 2Ohm contact resistance this would result in an error of only 1.3%, if remaining uncorrected
On reading the above, could i take a 7805 and get 10mA and 100mA by using two resistors at its o/p?
Can you tell me how did you get that error factor.
|Measuring CR of Reed Switches.||Suresh R||03/22/06 05:24|
|Contact resistance?||Oliver Sedlacek||03/22/06 06:41|
|Correction : Sorry its 10mV to 2500mV||Suresh R||03/22/06 08:17|
|Voltage or current, pick one||Oliver Sedlacek||03/23/06 02:12|
|I can choose Test current as 10mA||Suresh R||03/23/06 03:09|
|typical constact resistance ?||Steve M. Taylor||03/23/06 05:38|
|yes, but||Erik Malund||03/23/06 06:52|
|No CR when closed?||Suresh R||03/23/06 09:46|
|If this was possible, you would not need||Erik Malund||03/23/06 10:37|
|current source with series resistor at||Suresh R||03/23/06 11:22|
|Yes||Erik Malund||03/23/06 11:48|
|constant current source||Terry Lingle||03/23/06 13:18|
|V=IR||Neil Kurzman||03/23/06 15:10|
|Specs & Description||Suresh R||03/24/06 04:47|
|resistor ?||Steve M. Taylor||03/24/06 01:45|
|Current source circuit for CR measuremen||Suresh R||03/24/06 10:06|
|Why not using...||Kai Klaas||03/24/06 10:35|
|Kind of||Neil Kurzman||03/24/06 18:06|
|And...||Kai Klaas||03/24/06 20:38|
|7805 and get 10mA and 100mA||Suresh R||03/25/06 04:48|
|reply - thermo-potentials||Suresh R||03/26/06 03:39|
|since you work for the manufacturer||Erik Malund||03/26/06 10:50|
|Chopper||Kai Klaas||03/26/06 20:04|
|Chopper schematic||Kai Klaas||03/27/06 05:58|
|Thanks very much Kai.||Suresh R||03/27/06 10:35|
|Reply : Chopper Schematic||Suresh R||03/28/06 11:36|
|Answers||Kai Klaas||03/28/06 19:58|
|what about a chopper stabilized op-amp?||Erik Malund||03/29/06 06:14|
|Yur.||Steve M. Taylor||03/29/06 07:22|
|Yes, but...||Kai Klaas||03/29/06 08:36|
|AC components , VCR, DCR||Suresh R||03/29/06 11:59|
|Answers||Kai Klaas||03/29/06 20:18|
|Demodulation?||Oliver Sedlacek||03/30/06 01:06|
|This would be the Lock-in scheme||Kai Klaas||03/30/06 05:35|
|Average Value, VCR & DCR Calculation||Suresh R||03/30/06 05:30|
|Quite simple||Kai Klaas||03/30/06 05:45|
|Analysis for Usig o/p||Suresh R||03/30/06 11:56|
|Answers||Kai Klaas||03/30/06 20:33|
|I thank you very much Kai||Suresh R||03/31/06 04:48|
|Test Condition: 10mA, 50mV||Suresh R||04/19/06 10:06|
|Switching condition||Kai Klaas||04/19/06 10:14|
|Remember Ohm's law?||Richard Erlacher||03/23/06 12:50|