| ??? 01/16/05 14:02 Read: times |
#85047 - Being more concrete Responding to: ???'s previous message |
Kai said:
Connect first a load of >1MOhm, then 2kOhm (or even less) and observe how the signal goes down. From this signal damping the unknown source impedance can easily be calculated. Let 'Us' be the measured output signal with negligible load (>1MOhm, or so) and 'Ul' be the measured output signal across known load impedance 'Rl', with 'Rl' being in the kOhm range or even less. Then the source impedance 'Rs' can be calculated by Rs = (Us / Ul - 1) x Rl An example: Connecting a DVM with input impedance of 10MOhm yields a signal voltage of Us = 4.80V. Across a connected load resistance of Rl = 2kOhm a signal of Ul = 4.68V is measured. Then, above formula yields Rs = (4.80V / 4.68V - 1) x 2kOhm = 51 Ohm So, source impedance of device is about 50Ohm. Kai |
| Topic | Author | Date |
| Source Impedance | 01/01/70 00:00 | |
| Re | 01/01/70 00:00 | |
| Impedance measurement | 01/01/70 00:00 | |
| Being more concrete | 01/01/70 00:00 | |
| What about my Rogowski Coils. | 01/01/70 00:00 | |
| Already answered in detail! | 01/01/70 00:00 | |
| Re: ' Detailed Answer' | 01/01/70 00:00 | |
| Bridge | 01/01/70 00:00 | |
| What Bridge, | 01/01/70 00:00 | |
| bridge | 01/01/70 00:00 | |
| and ... | 01/01/70 00:00 | |
| Using an OPamp | 01/01/70 00:00 | |
| Using OpAmp | 01/01/70 00:00 | |
| Some disadvantages | 01/01/70 00:00 | |
| Correct formula | 01/01/70 00:00 | |
| Thanks Kai, | 01/01/70 00:00 | |
| LCR meters quite common | 01/01/70 00:00 | |
Re: LCR Meter. | 01/01/70 00:00 | |
| Resonant coupling... | 01/01/70 00:00 | |
| Sorry! | 01/01/70 00:00 | |
| Go with the rule of Thumb | 01/01/70 00:00 | |
| No more than about 10kOhm | 01/01/70 00:00 | |
| Line drops | 01/01/70 00:00 | |
| Thicker cable | 01/01/70 00:00 | |
| Freq domain analysis | 01/01/70 00:00 | |
| re: Source Impedance and driver types | 01/01/70 00:00 | |
| universal solution | 01/01/70 00:00 | |
| Thanks .... | 01/01/70 00:00 |