| ??? 05/31/05 11:26 Read: times |
#94137 - No way Responding to: ???'s previous message |
Shivani said:
I want to make 10k variation of resistance using parallel network of 12 resistances and switching them through microcontroller,please tell me how to calculate each resistance to get minimum step variation,switching will be done in binary(2^12=4096)combination. I don't know of such a scheme, and I think such a scheme will not exist. The reason is, that paralleling resitors isn't a linear operation, like putting them in series: Rg = R1 + R2 + ... +Ri instead of 1 / Rg = 1 / R1 + 1 / R2 + ... + 1 / Ri. Also, you will never achieve this 12 bit precision, just because the imperfections of available switches. Analog switches showing less resistance than 100Ohm are difficult to get. But even if you find one, than off-capacitance will be too high very probably. Kai |
| Topic | Author | Date |
| resistor network | 01/01/70 00:00 | |
| please clarify | 01/01/70 00:00 | |
| re please clarify | 01/01/70 00:00 | |
| Audio? | 01/01/70 00:00 | |
| nope audio | 01/01/70 00:00 | |
| then go binary | 01/01/70 00:00 | |
| re go binary | 01/01/70 00:00 | |
| Buy a digital pot? | 01/01/70 00:00 | |
| Many different digital pots | 01/01/70 00:00 | |
| Weighted Resistance for D/A Converter? | 01/01/70 00:00 | |
| Even R-2R will do.. | 01/01/70 00:00 | |
| Even R-2R will do.. | 01/01/70 00:00 | |
| No way | 01/01/70 00:00 | |
reply | 01/01/70 00:00 |