It also gives you better control over the two different currents, but it isn't free. Resistors are really cheap (unless you have super high requirements), and a resistor generally doesn't take up a lot of space. Is the cost significant? It really depends. Just be aware that sometimes the arrangement of parts does matter, and other times it doesn't. It's not unreasonable because a typical small LED's current is below the limit of being safe to drive directly from the MCU, but is slightly worry-some if you have a lot of other stuff going on. Usually these are, in the basic form, just an adjustable current controller with a potmeter for manual adjusting. Ive looked at a couple of the DIY schematics. To get a current to run trough a diode, you need to apply a slightly more positive voltage on the anode, than on the cathode. It's unclear from the original question if the kit/tutorials you're using have this type of LED driving circuit. In electronics, anode and cathode are terms used when dealing with diodes and tubes. This is an extra part we would have to have in our design meaning extra cost and space. If we instead moved R1 above Q1 or even above D1, we would have to add an additional resistor between MCU output and Q1 to limit the base current. In the above schematic we are using the resistor R1 to both limit current flowing through the LED as well as limiting the base current (current from MCU output to R1). Simulate this circuit – Schematic created using CircuitLab You know that for this reaction to work, the electrons need a wire of some sort or some way of conducting the. By cleverly placing the resistor it can serve multiple functions at the same time, thus allowing you to reduce the part count and save some money/space. The anode and cathode are both on the same piece of iron but different regions of it. For example, sometimes people will use a BJT transistor to allow for higher current drives through the LED because micro controller pins are limited to low current outputs. However, there are designs for driving LED's using transistors where choosing where you place your resistor does matter. You have non-reactive components (ideally, which is pretty close to reality) thus any current flowing into the diode/resistor must flow out, thus current would be limited equally well by having the resistor on either the anode or cathode side. LEDs or Light Emitting Diodes don’t come with any labeling on it to identify Cathode (-ve,GND) or Anode (+ve). Sometime the diode symbol creates confusion too.Identifing a LEDs the cathode and anode of a led is very easy by looking inside. Usually as RedGrittyBrick said it doesn't matter. So for identification, led’s comes with a unique way to identify its terminals as Anode or Cathode.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |