| Kai Klaas 03/27/06 05:58 Read: 1711 times Germany |
#113187 - Chopper schematic Responding to: Kai Klaas's previous message |
Kai said:
The best way to eliminate the influence of offset voltages, voltage drops of input bias currents of OPamps and thermo potentials of contacts is to use a chopper. A chopper modulates the current through the contact in a suited way and takes only those components of signal voltage into calculation which result from this modulation. All other static DC components like offset voltage, voltage drops of input bias currents or thermo potentials will vanish by this methode. You could try the following scheme: 
Kai |
| 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 |