What voltage is 600mA

Resistance, voltage and current


Resistors are electronic components. But resistance is also a property of other components. The electrical resistance R is defined as follows (Ohm's law):

Resistance = voltage / current
R = U / I
1 ohm = 1 volt / 1 ampere

Searched:Resistance R,    Current I,   Voltage U

Calculate resistance


Example: Not only a resistor but also an incandescent lamp has resistance. However, it is a variable property of the incandescent lamp that can only be specified for certain operating conditions. A bicycle taillight bulb, for example, has a voltage of 6 V and a current of 0.1 A. At its nominal voltage, it has a resistance of 60 ohms:

R = U / I
R = 6 V / 0.1 A
R = 60 ohms

To do this, an online calculator: Change the input fields for voltage and current. The resistance will then be displayed automatically. As in many circuit diagrams, the ohm symbol has been replaced by "R".
In electronics, most of the resistances are higher and the currents are lower. That is why there is a second online calculator in mA and kOhm. Example: What is the resistance if a current of 0.4 mA is measured at a voltage of 5 V? Answer: The resistance is 12.5 kOhm.




Calculate amperage

Sometimes you know the resistance and the connection voltage, but not the current strength. Which current flows e.g. through a resistor with 470 Ohm at a voltage of 12 V? To do this, you have to change Ohm's law:

Amperage = power / voltage
I = U / R
I = 12 V / 470 R
I = 0.026 A = 26 mA

Again, one often prefers to calculate in kOhm and mA .:


Calculate voltage

If you know the resistance and the amperage, but not the voltage, the formula has to be rearranged again. The question is, for example: What is the output voltage of a transmitter at the 50 ohm output if the current is 2 A?

Voltage = power / current
U = R * I
U = 50 R / 2 A
U = 100 V

And again in mA and kOhm: What is the voltage across a 4.7 kOhm resistor when the current is 2 mA? Answer: 9.4V.

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