Created equivalent_resistance under Electronics (#6782)

* Create resistor_equivalence.py

* Update resistor_equivalence.py

* Update electronics/resistor_equivalence.py

removed an unnecessary space

Co-authored-by: Caeden <caedenperelliharris@gmail.com>

* Update resistor_equivalence.py

fixed the snake_case requirement

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Update resistor_equivalence.py

finalize the naming convention errors (hopefully)

* Update resistor_equivalence.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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Co-authored-by: Caeden <caedenperelliharris@gmail.com>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>

electronics/resistor_equivalence.py

@@ -0,0 +1,58 @@
+# https://byjus.com/equivalent-resistance-formula/
+
+from __future__ import annotations
+
+
+def resistor_parallel(resistors: list[float]) -> float:
+    """
+    Req = 1/ (1/R1 + 1/R2 + ... + 1/Rn)
+
+    >>> resistor_parallel([3.21389, 2, 3])
+    0.8737571620498019
+    >>> resistor_parallel([3.21389, 2, -3])
+    Traceback (most recent call last):
+        ...
+    ValueError: Resistor at index 2 has a negative or zero value!
+    >>> resistor_parallel([3.21389, 2, 0.000])
+    Traceback (most recent call last):
+        ...
+    ValueError: Resistor at index 2 has a negative or zero value!
+    """
+
+    first_sum = 0.00
+    index = 0
+    for resistor in resistors:
+        if resistor <= 0:
+            raise ValueError(f"Resistor at index {index} has a negative or zero value!")
+        first_sum += 1 / float(resistor)
+        index += 1
+    return 1 / first_sum
+
+
+def resistor_series(resistors: list[float]) -> float:
+    """
+    Req = R1 + R2 + ... + Rn
+
+    Calculate the equivalent resistance for any number of resistors in parallel.
+
+    >>> resistor_series([3.21389, 2, 3])
+    8.21389
+    >>> resistor_series([3.21389, 2, -3])
+    Traceback (most recent call last):
+        ...
+    ValueError: Resistor at index 2 has a negative value!
+    """
+    sum_r = 0.00
+    index = 0
+    for resistor in resistors:
+        sum_r += resistor
+        if resistor < 0:
+            raise ValueError(f"Resistor at index {index} has a negative value!")
+        index += 1
+    return sum_r
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()