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How to select resistor values in electronic circuits?
V = R/I, where V is the voltage produced across the resistor, R is the resistor in Ohms and I is the current passing by way of the resistor in Amps. Let’s think as an illustration, a 1 amp current is passed by way of a 2 ohm resistor, resolving this in the above formula delivers:
How to calculate resistor value for LED lighting?
The formula Resistor = (Battery Voltage – LED voltage) / desired LED current. So assuming a 12-volt power source and a white LED with the desired current of 10 mA; The formula becomes Resistor = (12-3.4)/.010 which is 860 ohms. Since this is not a standard value I would use an 820-ohm resistor.
How to calculate the current limiting resistor value?
There are four steps to selecting the proper current limiting resistor value (s): Using the desired operating characteristics and LED specs, solve the appropriate equations for the “ideal” resistor values. Select appropriate “real” resistor values.
Which is the correct resistor for a white LED?
Resistor = (Battery Voltage – LED voltage) / desired LED current. So assuming a 12-volt power source and a white LED with the desired current of 10 mA; The formula becomes Resistor = (12-3.4)/.010 which is 860 ohms. Since this is not a standard value I would use an 820-ohm resistor.
What should the voltage drop be over a resistor?
That means the voltage drop over the resistor will be 9V-2V = 7V. So we need a resistor with a power rating of at least 140 mW. But preferably more. A rule of thumb is to find a resistor with twice the power rating. Here I would choose a 250 mW resistor since those are the most standard ones.
How to calculate the dissipation of a resistor?
Power dissipation in a resistor can be calculated with the formula. where P is power in Watt, V is the voltage drop over the resistor and R is the resistance of the resistor in Ohm. Let us look at an example: In this circuit, we use a LED with a voltage drop of about 2V.
How many times should the current flow through a resistor?
Here’s a very rough rule of thumb: The current flowing through the two resistors (assuming no input current) should be 10 to 1000 times more than the input current. The more current is flowing through these resistors, the less the input current will effect things.
How to choose the best resistor for an amplifier?
If you’re building an amp from scratch, use newer metal-film or metal-oxide in the input stages, and experiment with carbon comp. flavoring in the high voltage areas of the output. Finally, find a good median between the resistor’s power rating and what is required for the application.
How to calculate the sense resistor value Fo Maxim Integrated?
Entering V IN into Equation 2, we get Equation 3 to calculate the sense resistor value. For a 5mA current range example, select range B, which has a maximum current of 20mA, by setting data bits RS2, RS1, and RS0 (0, 1, 0).
How is the noise level of a resistor measured?
The current noise level in a resistor is commonly expressed in units of µV/V or in decibels (in terms of Noise Index [NI] dB ) [NI]dB = 20log [ (u / U) • 106 ] where u is root mean square noise voltage over a decade bandwidth, and U is the DC voltage drop across the resistor. Both u and U are measured in volts.
How does the type of a resistor affect its behavior?
The model describes how the actual resistor’s characteristics make its electrical behavior depend on frequency and on how voltage and current are applied to it. FIGURE 2. This is a model of how a resistor actually behaves in a circuit. The type of resistor determines the importance of each component.
How to calculate resistors in parallel and series?
By the end of this section, you will be able to: Draw a circuit with resistors in parallel and in series. Calculate the voltage drop of a current across a resistor using Ohm’s law. Contrast the way total resistance is calculated for resistors in series and in parallel.
How is the series inductance of a resistor determined?
FIGURE 2. This is a model of how a resistor actually behaves in a circuit. The type of resistor determines the importance of each component. The series inductance, L S, is primarily created by the leads attached to the resistor.