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To drop a 12 volt source to 6 volts with a resistor, you have to drop 6 volts. The value of the resistor you need would be 6 divided by the current the device pulls in amps.
For example, if the device pulls a half an amp the resistor has to be 6/0.5 or 12 ohms. As this device runs on 6 volts and draws 1/2 amp, it's wattage is 3 watts (volts x Amps). Common practice is to double this, or the resistor will probably get too hot and may open. I'd use a 10 watt to resistor to maintain a good margin for safety, and they're readily available.
Use a 12 ohm, 10 watt resistor.
Wiki User
∙ 10y ago
Wiki User
∙ 10y agoFor 1 amp you need 3 ohms, for 1 milliamp you need 3 kilohms.
Wiki User
∙ 13y agoTo select resistor depend on how much current pass through the circuit.example when curent of 1A flow you need resistor of 1ohm,when current of 2A flow you need resistor of 0.5ohm.
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What is the symbol used to represent a volt drop within an electric circuit?
You usually use V for volts. There can also be a subscript. Say for the voltage drop of a resistor could be called VR.
What is the purpose of a resistor in an electronic circuit If the resistor converts energy to heat then are you wasting energy any time you use a resistor?
In its simplest use a resistor in a circuit is used to limit the amount of current flow, or to decrease the amount of voltage applied to a device. One example is you had a 12 volt battery and you need/ wanted to connect it to a device that ran on 9 volts then a resistor can be chosen to reduce the 12 volts to the 9 volts required.
Why is a resistor used to operate an LED?
To calculate the current through an LED, use the following formula Current = (Source_voltage - Led_voltage_drop)/Resistance Now if you didn't use a resistor, the you only have the resistance in the wire, which is very small (eg .001 ohm). So if you have for instance a 9V battery, and a 2.1 volt drop across the LED, the resultant current would be so high, it would destroy the LED. We put a resistor in to lower the current to an acceptable range (often 20-30ma)
Which voltage regulator is best to use lm140 or lm78xx?
A: Neither these are fixed regulator and the lm140 is ancient. My choice for any regulator is LM117 since i can get 1.25 volts to over 30 volts with two resistor,
What is a potential divider and what does it do?
The most common type is resistive division. Say we have a source of V volts and we wish to apply a portion of the V volts (aV where a is between 0 and 1) to a load of resistance R. We can place a resistor R2 in series with load R to drop off the unwanted part of the voltage V. The math is a = R / (R + R2). This only works if the resistors are constant. For a changing load other methods are necessary. Say the load needs 5 volts and it draws 10 milliamperes at 5 volts, but the supply is 10 volts. The effective load resistance is 500 ohms. A 500 ohm resistor in series with the load would drop off the unwanted 5 volt excess. Suppose the load changes by 10%, but we wish to hold load voltage to 5%. We can place a 500 ohm resistor in parallel with the load and use a 250 ohm resistor to drop the voltage to 5 volts. The voltage change is now only 5% for a 10% load change.
What is the symbol used to represent a volt drop within an electric circuit?
You usually use V for volts. There can also be a subscript. Say for the voltage drop of a resistor could be called VR.
If the volts going in equals 5 and there is a resistance that equals 6 what would be the volts coming out?
The question is a bit ambiguous, but I will try to address it. If the 6 ohm resistance is in series with another resistance then some of the 5 volts would be dropped across the 6 ohm resistance and the remainder of the voltage would be dropped across the other resistance. To calculate the voltage, use the 'resistor voltage divider equation' (Google it). If the 5 volts is applied across only a 6 ohm resistance, then the top of the resistor is at 5 volts and the bottom of the resistor would be at 0 volts. The resistor would drop all of the voltage.
What size resistor is needed to drop from 5vdc to 3vdc?
use Ohm's law: to drop 2 volts, V = I x R 2 = current x resistance resistance = 2 / current. So you need to know the current
What causes a chiller voltage to drop from 480 volts to 440 volts?
the use and consistency of the use
What is the purpose of a resistor in an electronic circuit If the resistor converts energy to heat then are you wasting energy any time you use a resistor?
In its simplest use a resistor in a circuit is used to limit the amount of current flow, or to decrease the amount of voltage applied to a device. One example is you had a 12 volt battery and you need/ wanted to connect it to a device that ran on 9 volts then a resistor can be chosen to reduce the 12 volts to the 9 volts required.
How do you reduce 48 volts dc to 12 volts dc with resistors?
Yes. You can use a voltage divider. Say, for instance, one 1KOhm resistor in series with a 3KOhm resistor. Connect the 3k resistor to the 48 volts and connect the 1k resistor to ground. The 1k resistor will have 12 volts acress it. These resistors need to be at least 1 watt each as they are going to dissipate 0.576 watts and get warm. Now, if you attempt to pull power from the 1k resistor, note that regulation will be poor because the impedance of the load will go in parallel with the 1k resistor and change its value.
What resistor should you use to get 9v to 6v?
You can only use a resistor to drop a voltage at a constant current. If you know the current, use Ohm's law to calculate the resistor value.
How do you convert 110 volts into 30 volts?
AC - use a step-down transformer. DC - simplest but most wasteful, use a dropping resistor (in series). Otherwise it is costly.
What size resistor to change 12 volts to 3 volts for a led?
Assuming that you're talking about 12V DC you would use a 4 ohm resistor. If you mean AC then you would need a step-down transformer with a 4:1 ratio.
How do you Decrease 8000 Volts to 800 volts?
Use a step-down voltage transformer or find a resistor capable of using up 7200 V in series with the required 800V load
What size resistor is needed to allow a 220 volt coil in a relay operate on 277 volts?
You will need to know the amount of current flowing through the coil when 220 volts is applied across it. A resistor in series with the coil will limit the current so that the coil only sees 220 volts. The resistor will need to drop 57 volts. So, 57 volts divided by the current in amps will give you your required resistance. You will need a resistor with a high power dissipation rating with 57 volts across it. Your resistor will probaly need to dissipate several watts. For example: A 220 volt coil with 300 milliamps (.3 amps) will require a resistor of 733 ohms. The power dissipation of the resistor would need to be 17.1 Watts! You might try using a light bulb as a series resistor. Ensure that it can handle 57 volts. To complicate matters, is that AC or DC you are using? AC relays have inductance build in, in order to increase the specific "ac resistance", thus the same coil could use as little as 0,001A so you will need a very low value resistor. Anyway, if any 220V relay uses as much as 300mA, I doubt if you will be able to pick it up with one hand! Such a relay coil will draw about 66W of power! I have a 16A rated contact 230V relay. Its current is 0,0015A that is equivelant to 0.33W at 220V!
Why is a resistor used to operate an LED?
To calculate the current through an LED, use the following formula Current = (Source_voltage - Led_voltage_drop)/Resistance Now if you didn't use a resistor, the you only have the resistance in the wire, which is very small (eg .001 ohm). So if you have for instance a 9V battery, and a 2.1 volt drop across the LED, the resultant current would be so high, it would destroy the LED. We put a resistor in to lower the current to an acceptable range (often 20-30ma)
