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Can a NPN transistor be used to drive multiple LEDs?
Using an NPN transistor to drive multiple LEDs from a PIC microcontroller output. Since standard 3mm, 5mm, 8mm and 10mm LEDs only require around 15mA to operate, we can use a small NPN transistor to drive them. Some transistors that are suitable for use in LED driving applications are listed below.
How to protect LEDs from over voltage surges?
A surge protection subassembly that can suppress excessive surges to lower voltage levels is an optimal way to protect the LED luminaire investment. Extracted from Littelfuse_Varistor_LSP05_LSP10_Surge_Protection_Modules_Flyer.pdf
What causes transient surges in AC power lines?
Over-voltage transient surges can occur in AC power lines as the result of nearby electrical equipment being switched on/off. Nearby lightning strikes can also generate transient surges in AC power lines, especially in outdoor environments. This type of indirect lightning energy from storms can adversely affect outdoor LED lighting installations.
Are there plans to phase out incandescent lighting?
By Teddy To, Technical Marketing Manager, PLED LED Protection Devices, Littelfuse. Countries with the most advanced economies have well-established plans and programmes to phase out incandescent lighting. That shouldn’t be surprising given that lighting accounts for about 25% of global energy consumption.
Why is there no current in a LED driver circuit?
LED Driver Circuit. When the switch of the circuit is open, no current flows to the base of the transistor. Therefore, the transistor cannot turn on. Bipolar junction transistors need base current and sufficient positive voltage to the collector in order to provide amplification. So with no current, the transistor nor the LED turns on.
Can a transistor be used as a driver for an led?
An LED driver is an electronic circuit that utilises a transistor to switch power to an LED. Usually, the signal from a microcontroller, or logic gate, does not possess sufficient drive current to power an LED directly. If the LED has a higher power requirement, then it is best to use an NPN transistor as a driver.
How to build a simple LED driver circuit?
How to Build a Simple LED Driver Circuit. In this project, we will show how to build a simple LED driver circuit. A LED driver circuit is a circuit which can power on and light an LED>. We will simply use a transistor and a few resistors to bring about a circuit which, with minimal current, can produce enough current to drive and light an LED.
Can a transistor handle four LEDs at a time?
As you say, the transistor in the first circuit needs to be able to handle the combined LED current. For four normal indicator LEDs, that is not much of a limitation. Depending on the voltage of the LEDs, you might be able to drive two at a time in series with a single resistor.
Can you drive two LEDs at a time?
Depending on the voltage of the LEDs, you might be able to drive two at a time in series with a single resistor. For example, if these are red with 1.8 V forward drop, and the transistor goes to 200 mV in saturation, then there is still 1.2 V left for a resistor to set the current.
How to turn on multiple LEDs with Arduino?
Wire the first led’s cathode to the next led’s anode, and one resistor per pair. You should use the pin on the Arduino to control a transistor that turn on a relay and the relay contacts turn on the all the LEDs by apply ground.