THE HEIGHTS OF TECHNOLOGY: # SIMPLE ELECTRICAL CALCULATOR

● Ohm's law - calculator and formulas ●

Resistance (ohms), current (amps), and voltage (volts)

Ohm's Law is the linear proportionality between current and voltage that occurs for most conductors
of electricity. A graph of voltage against current is a straight line. The gradient is the resistance.

Practitioners rarely speak of potential difference, when electrical voltage (drop) is meant.

= reset.

V = R × I I = V / R R = V / I

The formulas of Ohm's Law

Ohm's Law can be rewritten in three ways for calculating current, resistance, and voltage.
If a current I should flow through a resistor R, the voltage V can be calculated.V = R × I

If there is a voltage V across a resistor R, a current I flows through it. I can be calculated. I = V / R

If a current I flows through a resistor, and there is a voltage V across the resistor R can be calculated.R = V / I

Name	Formula sign	Unit	Symbol
voltage	V or E	volt	V
current	I	ampere (amp)	A
resistance	R	ohm	Ω
power	P	watt	W

Tip: Ohm's magic triangle

The magic V I R triangle can be used to calculate all formulations of ohm's law.
Use a finger to hide the value to be calculated. The other two values then show
how to do the calculation.

The symbol I or J = Latin: influare, international ampere, and R = resistance. V = voltage,
electric potential difference, also called voltage drop, or E = electro motive force (EMF = voltage).

If you need the unit of power P = V × I look for the

Big Power Formulas:
Calculations: power, voltage, current, resistance, and power

Some are of the opinion that Georg Simon Ohm calculated the "specific resistance".
Therefore they believe that only this can be the true ohm's law.

	Value of the Resistance

R	= Resistance	Ω
ρ	= Electrical resistivity	Ω·m
l	= Cable length	m
A	= Cross-sectional area	m²

Electrical conductivity (conductance) σ (sigma) = 1/ρ
Specific electrical resistance (resistivity) ρ (rho) = 1/σ

Electrical conductors	Electrical conductivity Electrical conductance	Electrical resistivity Specific resistance
silver	σ = 62	ρ = 0.0161
copper	σ = 58	ρ = 0.0172
aluminium	σ = 36	ρ = 0.0277

Simply enter the value to the left or the right side.
The calculator works in both directions of the ↔ sign.

The value of the electrical conductivity (conductance) and the specific electrical resistance
(resistivity) is a temperature dependent material constant. Mostly it is given at 20 or 25°C.

Resistance R = ρ × (l / A) or R = l / (σ × A)

For all conductors the specific resistivity changes with the temperature. In a limited
temperature range it is approximately linear:

where α is the temperature coefficient, T is the temperature and T₀ is any temperature,
such as T₀ = 293.15 K = 20°C at which the electrical resistivity ρ (T₀) is known.

Cross-sectional area - cross section - slice plane

Now there is the question:
How can you calculate the cross sectional area (slice plane) A
from the wire diameter d and vice versa?

Calculation of the cross section A (slice plane) from diameter d:

r = radius of the wire
d = diameter of the wire

Calculation diameter d from cross section A (slice plane):
Formel Berechnung Durchmesser aus Querschnitt

Cross section A of the wire in mm² inserted in this formula gives the diameter d in mm.

Calculation − Round cables and wires:
• Diameter to cross section and vice versa •

Electrical voltage V = I × R (Ohm's law)

Electrical voltage = amperage × resistance

Please enter two values, the third value will be calculated.

Electric power P = V × I (Power law)

Electric power = voltage × amperage

Please enter two values, the third value will be calculated.

How electricity works.
Ohm's Law clearly explained.

● Parallel Resistor Calculator ●

Parallel Resistance Finder

Please enter two resistor values, the third value will be calculated.
You can even enter the total resistance and one known resistance.

Equation for the calculation of the resistances R₁ and R₂ connectet in parallel:

Calculation of the necessary parallel resistor R₂, when R₁ and the total resistance R_total is given:

Calculation of the necessary parallel resistor R₁, when R₂ and the total resistance R_total is given:

The first step is to clear all fractions by multiplying by the lowest
common denominator, that is R_t × R₁ × R₂ ... so we get:
1/R_t = 1/R₁ + 1/R₂
R_t × R₁ × R₂[1/R_t = 1/R₁ + 1/R₂]
R₁ × R₂ = R_t × R₂ + R_t × R₁ then collect terms with R₁ and solve
R₁ × R₂ − R_t × R₁ = R_t × R₂
R₁(R₂ − R_t) = R₂ × R_t
and finally:
R₁ = R₂ × R_t / (R₂ − R_t)

Notice: This calculator can also solve other math problems. Calculating resistors in parallel is
precisely the same as the calculations required for inductors in parallel or for capacitors in series.

• Search resistances R₁ and R₂, when the target resistance (equivalent resistance) is known •

Calculation: Resistor pairs - reverse engineered calculator

• Many resistors in parallel calculator •

This calculator determines the resistance of up to 10 resistors in parallel.
Enter resistances into the boxes below and when all values have been input,
click on the 'calculate' button and the result will appear in the box below that button.
As a test, if you enter resistances of 4, 6, and 12 ohms, the answer should be 2 ohms.
Notice: Manually clearing the boxes does not reset stored values.

Ohm's law - calculator and formulas

Two resistors in parallel and resulting resistance
Resistance ranging 1 to 100 ohm

R2	R1
R2	1	1.5	2.2	3.3	4.7	6.8	10	15	22	33	47	68
1	0.5	0.6	0.69	0.77	0.83	0.87	0.91	0.93	0.95	0.97	0.98	0.99
1.5	0.6	0.75	0.89	1.03	1.14	1.22	1.30	1.36	1.40	1.43	1.45	1.46
2.2	0.69	0.89	1.1	1.32	1.50	1.66	1.82	1.92	2.0	2.06	2.10	2.13
3.3	0.77	1.03	1.32	1.65	1.94	2.22	2.48	2.70	2.87	3.00	3.08	3.14
4.7	0.83	1.14	1.50	1.94	2.35	2.78	3.20	3.58	3.87	4.12	4.27	4.39
6.8	0.87	1.22	1.66	2.22	2.78	3.40	4.05	4.68	5.19	5.64	5.94	6.18
10	0.91	1.30	1.82	2.48	3.20	4.05	5.0	6.0	6.9	7.7	8.3	8.7
15	0.93	1.36	1.92	2.70	3.58	4.68	6.0	7.50	8.9	10.3	11.4	12.2
22	0.95	1.40	2.00	2.87	3.87	5.19	6.9	8.9	11.0	13.2	15.0	16.6
33	0.97	1.43	2.06	3.0	4.12	5.64	7.7	10.3	13.2	16.5	19.4	22.2
47	0.98	1.45	2.1	3.08	4.27	5.94	8.3	11.4	15,0	19.4	23.5	27.8
68	0.99	1.46	2.13	3.14	4.39	6.18	8.7	12.2	16.6	22.2	27.8	34.0

Color Code Calculator - Resistor values with 4 color bands
E6 E12 E-24 resistors resistor table tables calculator band bands band bands row calculation color code colour black brown red orange yellow ohms DIN

Calculation of resistor values - 5 color bands
E-12 E-6 colour bands resistors resistor table tables calculator band bands row calculation color code black brown ohms DIN

Significant figures of nominal resistance
E-6 resistance tolerance (± 20%)
10	15	22	33	47	68

E-12 resistance tolerance (± 10%)
10	12	15	18	22	27	33	39	47	56	68	82

E-24 resistance tolerance (± 5 %)
10	11	12	13	15	16	18	20	22	24	27	30
33	36	39	43	47	51	56	62	68	75	82	91

E-48 resistance tolerance (± 2%)
10.0		10.5		11.0		11.5		12.1		12.7
13.3		14.0		14.7		15.4		16.2		16.9
17.8		18.7		19.6		20.5		21.5		22.6
23.7		24.9		26.1		27.4		28.7		30.1
31.6		33.2		34.8		36.5		38.3		40.2
42.2		44.2		46.4		48.7		51.1		53.6
56.2		59.0		61.9		64.9		68.1		71.5
75.0		78.7		82.5		86.6		90.9		95.3

E-96 resistance tolerance (± 1%)
10.0	10.2	10.5	10.7	11.0	11.3	11.5	11.8	12.1	12.4	12.7	13.0
13.3	13.7	14.0	14.3	14.7	15.0	15.4	15.8	16.2	16.5	16.9	17.4
17.8	18.2	18.7	19.1	19.6	20.0	20.5	21.0	21.5	22.1	22.6	23.2
23.7	24.3	24.9	25.5	26.1	26.7	27.4	28.0	28.7	29.4	30.1	30.9
31.6	32.4	33.2	34.0	34.8	35.7	36.5	37.4	38.3	39.2	40.2	41.2
42.2	43.2	44.2	45.3	46.4	47.5	48.7	49.9	51.1	52.3	53.6	54.9
56.2	57.6	59.0	60.4	61.9	63.4	64.9	66.5	68.1	69.8	71.5	73.2
75.0	76.8	78.7	80.6	82.5	84.5	86.6	88.7	90.9	93.1	95.3	97.6

E-192 resistance tolerance (± 0.5%)
10.0	10.1	10.2	10.4	10.5	10.6	10.7	10.9	11. 0	11. 1	11. 3	11. 4
11. 5	11. 7	11. 8	12.0	12.1	12.3	12.4	12.6	12.7	12.9	13.0	13.2
13.3	13.5	13.7	13.8	14.0	14.2	14.3	14.5	14.7	14.9	15.0	15.2
15.4	15.6	15.8	16.0	16.2	16.4	16.5	16.7	16.9	17.2	17.4	17.6
17.8	18.0	18.2	18.4	18.7	18.9	19.1	19.3	19.6	19.8	20.0	20.3
20.5	20.8	21.0	21.3	21.5	21.8	22.1	22.3	22.6	22.9	23.2	23.4
23.7	24.0	24.3	24.6	24.9	25.2	25.5	25.8	26.1	26.4	26.7	27.1
27.4	27.7	28.0	28.4	28.7	29.1	29.4	29.8	30.1	30.5	30.9	31.2
31.6	32.0	32.4	32.8	33.2	33.6	34.0	34.4	34.8	35.2	35.7	36.1
36.5	37.0	37.4	37.9	38.3	38.8	39.2	39.7	40.2	40.7	41.2	41.7
42.2	42.7	43.2	43.7	44.2	44.8	45.3	45.9	46.4	47.0	47.5	48.1
48.7	49.3	49.9	50.5	51.1	51.7	52.3	53.0	53.6	54.2	54.9	55.6
56.2	56.9	57.6	58.3	59.0	59.7	60.4	61.2	61.9	62.6	63.4	64.2
64.9	65.7	66.5	67.3	68.1	69.0	69.8	70.6	71.5	72.3	73.2	74.1
75.0	75.9	76.8	77.7	78.7	79.6	80.6	81.6	82.5	83.5	84.5	85.6
86.6	87.6	88.7	89.8	90.9	92.0	93.1	94.2	95.3	96.5	97.6	98.8