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More current = More brightness
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What is the effect on led by increasing or decreasing current?
An LED will shine brighter as more current is pushed through it. There is a dimishing return on this - at some point, increasing current will not increase the brightness very much, and will cost significantly more in terms of power.
Will a LED shine brighter if it is connected to a higher voltage?
A LED has a forward voltage drop dependent on it's composition. It is fairly constant within a small range of current flow. If the voltage is too high and the current is not limited, the LED will burn out. The brightness can be varied by varying the available current, but the voltage across the LED remains virtually the same.
How do we decrease the brightness of a bulb?
If the bulb is of the incandescent variety, then reducing the current in the circuit will do this.
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)
Why current will vary in a solar cell?
The current will of course vary with the intensity of the imparted light and with the temperature of the panel.
What is the effect on led by increasing or decreasing current?
An LED will shine brighter as more current is pushed through it. There is a dimishing return on this - at some point, increasing current will not increase the brightness very much, and will cost significantly more in terms of power.
What is the brightness and wavelength of the LED?
That depends on the LED in question
Will a LED shine brighter if it is connected to a higher voltage?
A LED has a forward voltage drop dependent on it's composition. It is fairly constant within a small range of current flow. If the voltage is too high and the current is not limited, the LED will burn out. The brightness can be varied by varying the available current, but the voltage across the LED remains virtually the same.
Do stars have the same brightness and sizes?
No. Stars vary greatly in size and brightness.
How are light bulbs measured?
Brightness of a light bulb depends on the power, current, resistance and size of the filament. Lumens is the unit of measurement for the brightness of a bulb. A bulb has more brightness if there is more power and current. Greater the resistance, less is the brightness.
Stars that can change their brightness?
the moon can vary its brightness and the pink elephant called aphadophalis
Can LED lights flash on and off?
yes i think so Yes, there are flashing l.e.ds. An ordinary l.e.d. can, of course, be flashed on and off by interrupting the current through it. There are products such as the LED-FLASHDIM available from LED-SUPPLIES.COM that will enable you to control how LED strip lighting flashes and at what speed and brightness levels
What makes LED lights dim up and down automatically when on Is it a capacitor or some other thing built in to the circuit?
LEDs are current based devices in that they will emit more light as more current passes through them. Light emitting diodes are like other diodes in that they require a certain voltage across them before they will pass a current. Typically, an LED will require between 2 and 4 volts. LEDs need a controlled current in order to prevent damage. Often, the current is controlled using a fixed voltage and a series resistor. The resistor will fix the current at a calculated level. If the voltage across the LED and resistor varies, so the current will also vary and hence the brightness as well. Although capacitors are often seen around LEDs in circuits, they do not directly play a part in controlling the light intensity. Many variable brightness LED circuits use a technique of pulse width modulation. A series of pulses at high frequency (1KHz upwards) are used to drive the LED. When the pulse in on, it will generate a voltage sufficient to turn on the LED at full brightness. When the pulse is off, the LED will also be off. With a very short pulse, the LED will be off far more than it is on so the LED will look dim. As the pulses get longer, the LED will be on for a greater proportion of the time so it will look brighter. Eventually, each pulse can be made so long that it will meet the next pulse in the stream of pulses. That means that the LED is on all the time and will be at maximum brightness. In some cases, the current switching may not be desirable so a capacitor might be added into the circuit. When the pulse is on, the capacitor will be charging so the voltage across the capacitor will increase. The LED and resistor will be drawing current all the time so as soon as the pulse is turned off, the voltage across the capacitor will reduce over time. If the width of the pulse is small, the average voltage across the capacitor and therefore across the LED and resistor will be small, so the brightness will be low. As the width of the pulse gets wider, the capacitor is charged more and the average voltage will rise as a result, so the LED glows brighter. The stream of pulses and the width of the pulses can be generated in several ways but it is common to use a processor such as a micro-controller rather than more traditional hardware.
What will happen to the lamp if current decreases?
brightness will decrease
Do the brightness of a lamp depend upon current?
yes
What does the brightness of a globe indicate?
The brightness of a globe can give an indication of the relative amount of electric current passing through it.
What are dimmers and resistors?
a dimmer is a device that allows you to vary the brightness of a light.
