feat: ✨ calculating the resitance of resistor using color codes (#9874)

Author: NinjaSoulPirate

electronics/resistor_color_code.py

@@ -0,0 +1,373 @@
+"""
+Title : Calculating the resistance of a n band resistor using the color codes
+
+Description :
+    Resistors resist the flow of electrical current.Each one has a value that tells how
+    strongly it resists current flow.This value's unit is the ohm, often noted with the
+    Greek letter omega: Ω.
+
+    The colored bands on a resistor can tell you everything you need to know about its
+    value and tolerance, as long as you understand how to read them. The order in which
+    the colors are arranged is very important, and each value of resistor has its own
+    unique combination.
+
+    The color coding for resistors is an international standard that is defined in IEC
+    60062.
+
+    The number of bands present in a resistor varies from three to six. These represent
+    significant figures, multiplier, tolerance, reliability, and temperature coefficient
+    Each color used for a type of band has a value assigned to it. It is read from left
+    to right.
+    All resistors will have significant figures and multiplier bands. In a three band
+    resistor first two bands from the left represent significant figures and the third
+    represents the multiplier band.
+
+    Significant figures - The number of significant figures band in a resistor can vary
+    from two to three.
+    Colors and values associated with significant figure bands -
+    (Black = 0, Brown = 1, Red = 2, Orange = 3, Yellow = 4, Green = 5, Blue = 6,
+    Violet = 7, Grey = 8, White = 9)
+
+    Multiplier - There will be one multiplier band in a resistor. It is multiplied with
+    the significant figures obtained from previous bands.
+    Colors and values associated with multiplier band -
+    (Black = 100, Brown = 10^1, Red = 10^2, Orange = 10^3, Yellow = 10^4, Green = 10^5,
+    Blue = 10^6, Violet = 10^7, Grey = 10^8, White = 10^9, Gold = 10^-1, Silver = 10^-2)
+    Note that multiplier bands use Gold and Silver which are not used for significant
+    figure bands.
+
+    Tolerance - The tolerance band is not always present. It can be seen in four band
+    resistors and above. This is a percentage by which the resistor value can vary.
+    Colors and values associated with tolerance band -
+    (Brown = 1%, Red = 2%, Orange = 0.05%, Yellow = 0.02%, Green = 0.5%,Blue = 0.25%,
+    Violet = 0.1%, Grey = 0.01%, Gold = 5%, Silver = 10%)
+    If no color is mentioned then by default tolerance is 20%
+    Note that tolerance band does not use Black and White colors.
+
+    Temperature Coeffecient - Indicates the change in resistance of the component as
+    a function of ambient temperature in terms of ppm/K.
+    It is present in six band resistors.
+    Colors and values associated with Temperature coeffecient -
+    (Black = 250 ppm/K, Brown = 100 ppm/K, Red = 50 ppm/K, Orange = 15 ppm/K,
+    Yellow = 25 ppm/K, Green = 20 ppm/K, Blue = 10 ppm/K, Violet = 5 ppm/K,
+    Grey = 1 ppm/K)
+    Note that temperature coeffecient band does not use White, Gold, Silver colors.
+
+Sources :
+    https://www.calculator.net/resistor-calculator.html
+    https://learn.parallax.com/support/reference/resistor-color-codes
+    https://byjus.com/physics/resistor-colour-codes/
+"""
+valid_colors: list = [
+    "Black",
+    "Brown",
+    "Red",
+    "Orange",
+    "Yellow",
+    "Green",
+    "Blue",
+    "Violet",
+    "Grey",
+    "White",
+    "Gold",
+    "Silver",
+]
+
+significant_figures_color_values: dict[str, int] = {
+    "Black": 0,
+    "Brown": 1,
+    "Red": 2,
+    "Orange": 3,
+    "Yellow": 4,
+    "Green": 5,
+    "Blue": 6,
+    "Violet": 7,
+    "Grey": 8,
+    "White": 9,
+}
+
+multiplier_color_values: dict[str, float] = {
+    "Black": 10**0,
+    "Brown": 10**1,
+    "Red": 10**2,
+    "Orange": 10**3,
+    "Yellow": 10**4,
+    "Green": 10**5,
+    "Blue": 10**6,
+    "Violet": 10**7,
+    "Grey": 10**8,
+    "White": 10**9,
+    "Gold": 10**-1,
+    "Silver": 10**-2,
+}
+
+tolerance_color_values: dict[str, float] = {
+    "Brown": 1,
+    "Red": 2,
+    "Orange": 0.05,
+    "Yellow": 0.02,
+    "Green": 0.5,
+    "Blue": 0.25,
+    "Violet": 0.1,
+    "Grey": 0.01,
+    "Gold": 5,
+    "Silver": 10,
+}
+
+temperature_coeffecient_color_values: dict[str, int] = {
+    "Black": 250,
+    "Brown": 100,
+    "Red": 50,
+    "Orange": 15,
+    "Yellow": 25,
+    "Green": 20,
+    "Blue": 10,
+    "Violet": 5,
+    "Grey": 1,
+}
+
+band_types: dict[int, dict[str, int]] = {
+    3: {"significant": 2, "multiplier": 1},
+    4: {"significant": 2, "multiplier": 1, "tolerance": 1},
+    5: {"significant": 3, "multiplier": 1, "tolerance": 1},
+    6: {"significant": 3, "multiplier": 1, "tolerance": 1, "temp_coeffecient": 1},
+}
+
+
+def get_significant_digits(colors: list) -> str:
+    """
+    Function returns the digit associated with the color. Function takes a
+    list containing colors as input and returns digits as string
+
+    >>> get_significant_digits(['Black','Blue'])
+    '06'
+
+    >>> get_significant_digits(['Aqua','Blue'])
+    Traceback (most recent call last):
+      ...
+    ValueError: Aqua is not a valid color for significant figure bands
+
+    """
+    digit = ""
+    for color in colors:
+        if color not in significant_figures_color_values:
+            msg = f"{color} is not a valid color for significant figure bands"
+            raise ValueError(msg)
+        digit = digit + str(significant_figures_color_values[color])
+    return str(digit)
+
+
+def get_multiplier(color: str) -> float:
+    """
+    Function returns the multiplier value associated with the color.
+    Function takes color as input and returns multiplier value
+
+    >>> get_multiplier('Gold')
+    0.1
+
+    >>> get_multiplier('Ivory')
+    Traceback (most recent call last):
+      ...
+    ValueError: Ivory is not a valid color for multiplier band
+
+    """
+    if color not in multiplier_color_values:
+        msg = f"{color} is not a valid color for multiplier band"
+        raise ValueError(msg)
+    return multiplier_color_values[color]
+
+
+def get_tolerance(color: str) -> float:
+    """
+    Function returns the tolerance value associated with the color.
+    Function takes color as input and returns tolerance value.
+
+    >>> get_tolerance('Green')
+    0.5
+
+    >>> get_tolerance('Indigo')
+    Traceback (most recent call last):
+      ...
+    ValueError: Indigo is not a valid color for tolerance band
+
+    """
+    if color not in tolerance_color_values:
+        msg = f"{color} is not a valid color for tolerance band"
+        raise ValueError(msg)
+    return tolerance_color_values[color]
+
+
+def get_temperature_coeffecient(color: str) -> int:
+    """
+    Function returns the temperature coeffecient value associated with the color.
+    Function takes color as input and returns temperature coeffecient value.
+
+    >>> get_temperature_coeffecient('Yellow')
+    25
+
+    >>> get_temperature_coeffecient('Cyan')
+    Traceback (most recent call last):
+      ...
+    ValueError: Cyan is not a valid color for temperature coeffecient band
+
+    """
+    if color not in temperature_coeffecient_color_values:
+        msg = f"{color} is not a valid color for temperature coeffecient band"
+        raise ValueError(msg)
+    return temperature_coeffecient_color_values[color]
+
+
+def get_band_type_count(total_number_of_bands: int, type_of_band: str) -> int:
+    """
+    Function returns the number of bands of a given type in a resistor with n bands
+    Function takes total_number_of_bands and type_of_band as input and returns
+    number of bands belonging to that type in the given resistor
+
+    >>> get_band_type_count(3,'significant')
+    2
+
+    >>> get_band_type_count(2,'significant')
+    Traceback (most recent call last):
+      ...
+    ValueError: 2 is not a valid number of bands
+
+    >>> get_band_type_count(3,'sign')
+    Traceback (most recent call last):
+      ...
+    ValueError: sign is not valid for a 3 band resistor
+
+    >>> get_band_type_count(3,'tolerance')
+    Traceback (most recent call last):
+      ...
+    ValueError: tolerance is not valid for a 3 band resistor
+
+    >>> get_band_type_count(5,'temp_coeffecient')
+    Traceback (most recent call last):
+      ...
+    ValueError: temp_coeffecient is not valid for a 5 band resistor
+
+    """
+    if total_number_of_bands not in band_types:
+        msg = f"{total_number_of_bands} is not a valid number of bands"
+        raise ValueError(msg)
+    if type_of_band not in band_types[total_number_of_bands]:
+        msg = f"{type_of_band} is not valid for a {total_number_of_bands} band resistor"
+        raise ValueError(msg)
+    return band_types[total_number_of_bands][type_of_band]
+
+
+def check_validity(number_of_bands: int, colors: list) -> bool:
+    """
+    Function checks if the input provided is valid or not.
+    Function takes number_of_bands and colors as input and returns
+    True if it is valid
+
+    >>> check_validity(3, ["Black","Blue","Orange"])
+    True
+
+    >>> check_validity(4, ["Black","Blue","Orange"])
+    Traceback (most recent call last):
+      ...
+    ValueError: Expecting 4 colors, provided 3 colors
+
+    >>> check_validity(3, ["Cyan","Red","Yellow"])
+    Traceback (most recent call last):
+      ...
+    ValueError: Cyan is not a valid color
+
+    """
+    if number_of_bands >= 3 and number_of_bands <= 6:
+        if number_of_bands == len(colors):
+            for color in colors:
+                if color not in valid_colors:
+                    msg = f"{color} is not a valid color"
+                    raise ValueError(msg)
+            return True
+        else:
+            msg = f"Expecting {number_of_bands} colors, provided {len(colors)} colors"
+            raise ValueError(msg)
+    else:
+        msg = "Invalid number of bands. Resistor bands must be 3 to 6"
+        raise ValueError(msg)
+
+
+def calculate_resistance(number_of_bands: int, color_code_list: list) -> dict:
+    """
+    Function calculates the total resistance of the resistor using the color codes.
+    Function takes number_of_bands, color_code_list as input and returns
+    resistance
+
+    >>> calculate_resistance(3, ["Black","Blue","Orange"])
+    {'resistance': '6000Ω ±20% '}
+
+    >>> calculate_resistance(4, ["Orange","Green","Blue","Gold"])
+    {'resistance': '35000000Ω ±5% '}
+
+    >>> calculate_resistance(5, ["Violet","Brown","Grey","Silver","Green"])
+    {'resistance': '7.18Ω ±0.5% '}
+
+    >>> calculate_resistance(6, ["Red","Green","Blue","Yellow","Orange","Grey"])
+    {'resistance': '2560000Ω ±0.05% 1 ppm/K'}
+
+    >>> calculate_resistance(0, ["Violet","Brown","Grey","Silver","Green"])
+    Traceback (most recent call last):
+      ...
+    ValueError: Invalid number of bands. Resistor bands must be 3 to 6
+
+    >>> calculate_resistance(4, ["Violet","Brown","Grey","Silver","Green"])
+    Traceback (most recent call last):
+      ...
+    ValueError: Expecting 4 colors, provided 5 colors
+
+    >>> calculate_resistance(4, ["Violet","Silver","Brown","Grey"])
+    Traceback (most recent call last):
+      ...
+    ValueError: Silver is not a valid color for significant figure bands
+
+    >>> calculate_resistance(4, ["Violet","Blue","Lime","Grey"])
+    Traceback (most recent call last):
+      ...
+    ValueError: Lime is not a valid color
+
+    """
+    is_valid = check_validity(number_of_bands, color_code_list)
+    if is_valid:
+        number_of_significant_bands = get_band_type_count(
+            number_of_bands, "significant"
+        )
+        significant_colors = color_code_list[:number_of_significant_bands]
+        significant_digits = int(get_significant_digits(significant_colors))
+        multiplier_color = color_code_list[number_of_significant_bands]
+        multiplier = get_multiplier(multiplier_color)
+        if number_of_bands == 3:
+            tolerance_color = None
+        else:
+            tolerance_color = color_code_list[number_of_significant_bands + 1]
+        tolerance = (
+            20 if tolerance_color is None else get_tolerance(str(tolerance_color))
+        )
+        if number_of_bands != 6:
+            temperature_coeffecient_color = None
+        else:
+            temperature_coeffecient_color = color_code_list[
+                number_of_significant_bands + 2
+            ]
+        temperature_coeffecient = (
+            0
+            if temperature_coeffecient_color is None
+            else get_temperature_coeffecient(str(temperature_coeffecient_color))
+        )
+        resisitance = significant_digits * multiplier
+        if temperature_coeffecient == 0:
+            answer = f"{resisitance}Ω ±{tolerance}% "
+        else:
+            answer = f"{resisitance}Ω ±{tolerance}% {temperature_coeffecient} ppm/K"
+        return {"resistance": answer}
+    else:
+        raise ValueError("Input is invalid")
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()