| Suresh R 03/22/06 05:24 Read: 1254 times Chennai India |
#112768 - Measuring CR of Reed Switches. |
Hello Everyone,
I need to develop a circuit to measure the contact Resistance of Reed switches. The Test current should be 10mA and 100mA The Test Voltage should be from 10mV to 2500V (variable) This is the spec available for the existing one (its an addon card). i would like to do a new one that could give the Test current and Test Voltage as mentioned above. i came accross the Kelvin four wire method as a suitable option to measure the contact resistance. But not sure of the supporting circuit, that could achieve the above rating. So, i would be happy if anyone could guide me with some suggestions in developing the circuit. Suggestions on alternate methods for measurement of CR will also prove to be useful. Thanking you all, suresh. |
| Topic | Author | Date |
| 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 |