LAB electronics tips#
Representation of unit of measure standard https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-7-rules-and-style-conventions-expressing-values
7.1 Value and numerical value of a quantity
The value of a quantity is its magnitude expressed as the product of a number and a unit, and the number multiplying the unit is the numerical value of the quantity expressed in that unit.
More formally, the value of quantity A can be written as A = {A}[A], where {A} is the numerical value of A when the value of A is expressed in the unit [A]. The numerical value can therefore be written as {A} = A / [A], which is a convenient form for use in figures and tables. Thus, to eliminate the possibility of misunderstanding, an axis of a graph or the heading of a column of a table can be labeled "t/°C" instead of "t (°C)" or "Temperature (°C)." Similarly, an axis or column heading can be labeled "E/(V/m)" instead of "E (V/m)" or "Electric field strength (V/m)."
Examples:
In the SI, the value of the velocity of light in vacuum is c = 299 792 458 m/s exactly. The number 299 792 458 is the numerical value of c when c is expressed in the unit m/s, and equals c/(m/s).
The ordinate of a graph is labeled T/(103 K), where T is thermodynamic temperature and K is the unit symbol for kelvin, and has scale marks at 0, 1, 2, 3, 4, and 5. If the ordinate value of a point on a curve in the graph is estimated to be 3.2, the corresponding temperature is T / (103 K) = 3.2 or T = 3200 K. Notice the lack of ambiguity in this form of labeling compared with "Temperature (103 K)."
An expression such as ln(p/MPa), where p is the quantity symbol for pressure and MPa is the unit symbol for megapascal, is perfectly acceptable, because p/MPa is the numerical value of p when p is expressed in the unit MPa and is simply a number.
Notes:
For the conventions concerning the grouping of digits, see Sec. 10.5.3.
An alternative way of writing c/(m/s) is {c}m/s, meaning the numerical value of c when c is expressed in the unit m/s.
Standard resistance table#
Table with E12 and E24 series
https://eepower.com/resistor-guide/resistor-standards-and-codes/resistor-values/#
table with color code
https://www.calculator.net/resistor-calculator.html
| Color | 1st, 2nd, 3rd Band Significant Figures |
Multiplier | Tolerance | Temperature Coefficient |
| 0 | × 1 | 250 ppm/K (U) | ||
| 1 | × 10 | ±1% (F) | 100 ppm/K (S) | |
| 2 | × 100 | ±2% (G) | 50 ppm/K (R) | |
| 3 | × 1K | ±0.05% (W) | 15 ppm/K (P) | |
| 4 | × 10K | ±0.02% (P) | 25 ppm/K (Q) | |
| 5 | × 100K | ±0.5% (D) | 20 ppm/K (Z) | |
| 6 | × 1M | ±0.25% (C) | 10 ppm/K (Z) | |
| 7 | × 10M | ±0.1% (B) | 5 ppm/K (M) | |
| 8 | × 100M | ±0.01% (L) | 1 ppm/K (K) | |
| 9 | × 1G | |||
| × 0.1 | ±5% (J) | |||
| × 0.01 | ±10% (K) | |||
| ±20% (M) |