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Resistor Types
From Transwiki
[edit] Resistor types
| Resistor Type | Ohm range Min | Ohm Range Max | Temp-co Min PPM | Temp-co Max PPM | Parasitics |
|---|---|---|---|---|---|
| Carbon | 1 | 22M | 400 | 1300 | low |
| Carbon Film (CF) | 10 | 10M | 500 | 800 | Mid |
| Metal Film (MF) | 10 | 1M | 25 | 1000 | mid |
| Metal Element | .0002 | 1 | 75 | 110 | ?? |
| Metal Foil | .0001 | 150k | 0.2 | 150 | ?? |
| Metal Oxide(MO) | 1 | 30M | 100 | 200 | ?? |
| Thick Film | .001 | 100G | 80 | 800 | Mid |
| Thin Film | .001 | 10M | 5 | 500 | Mid |
| Wire Wound | .005 | 50K | 20 | 600 | High |
| Diffused | ? | ? | ? | ? |
- Diffused resistors (inside an ICs) track well
- Parasitics can be of both capacitance and inductance.
- When working with high-voltage - pay attention to the rating
- Most applications de-rate the power rating by half.
- Metal oxide resistors are often good for more than 1/2 watt applications - tough and withstand transients.
[edit] Case to wattage
| Case size mils | Case Size metric | Mill Wattage | Wattage | Relative price |
|---|---|---|---|---|
| 01005 | 0402 | 0.031 | ||
| 0201 | 0603 | 0.05 | ||
| 0402 | 1005 | 0.0625 | 0.167 | 3.6 |
| 0603 | 1608 | 0.0625 | 0.1 | 2.10 |
| 0805 | 2012 | 0.100 | 0.125 | 2.50 |
| 1206* | 3216 | 0.125 | 0.250 | 3.90 |
| 1210 | 3225 | 0.250 | 0.333 | |
| 2010 | 5025 | 0.500 | 0.750 | |
| 2512 | 6432 | 1.00 | ||
| 2045 | 50??? | 1.00 | 2 |
Note - Resistors are normally de-rated by 50% for a good life span. The area of these chip resistors is the same no matter what wattage they are rated - the surface may be a different material, but the insides are still hotter if the manufacturer rates them higher. Conservative design would tell us to use the lower values. ®
