# Tagged Questions

143 views

### How do I quantitatively describe a system with 2 parallel diodes and a current source

What would happen in this system? How can I find the bias point of a circuit like this: Considering the LEDs are not perfectly matched. The 35mA are generated by a high precision stablizied current ...
355 views

### Voltage drop assumption on diodes (LEDs, etc.)

I've always wondered why is it valid to assume some voltage drop (different from the junction voltage drop) on diodes or LEDs from the power up of a circuit. It simplifies the analysis, but it's ...
598 views

### calculating resistance for LED strips to use as parking lamps and turn signals

I'm installing LED strips in my car's tail lamps to convert it from conventional bulbs to LEDs. I have a understanding of what I'm doing but not the complete knowledge to make the circuit work ...
488 views

### How do I select the Correct Diodes and Resistors for my LEDs?

I've got a 2009 Harley-Davidson XR1200 (that can be seen at the bottom of my bio in my profile). I've replaced the stock incandescent bulbs with nice looking LEDs; however, the stock bulbs were 2-way ...
224 views

### Dropping voltage for red channel on RGB LED

I'm looking at a Multicomp OSW-8349 RGB LED, which has a Vf of 3V min / 4V max for the green and blue channels, and a Vf of 1.8V min to 2.8V max for the red channel, at 350mA. I'm planning on ...
222 views

### Is this LED fixture safe for use with its current fabrication?

My father is currently interested in investing into a Ukrainian LED fixture manufacturer, and after he bought home a sample, I'm scared. There are 94 LEDs paired up with diodes, all in series, ...
273 views

### Using a diode or resistor, to supply minimal voltage to LED Driver (Help!)

I'm using a dual 60W LED multi-chip pendant lighting (a.k.a. "high bay" pendant light with two 60W LED chips). This light is using an RGB driver (one per multi-chip) that has a remote control to ...
2k views

### Driving an LED/Laser diode with a RF signal up to 20 MHz

I'm trying to design a circuit that will let me drive an LED or Diode laser with a RF signal up to ~20 MHz or so. Since the optical device will need to be biased with a DC current, a bias -t is a ...
287 views

### Anode RGB LED Arduino Hookup

My question is regarding the hookup of a radioshack bright rgb anode led. I have the led common going to a 5v supply and the other pins are going through a 330ohm resistor to 3 PWM output pins ...
2k views

### Zener Diode for Minimum Voltage Regulator

I forgot the name of it, but I remember one post where it said that you can use a zener diode as a "minimum voltage regulator". I don't think I used the right term for it, but here's what I'm doing. ...
414 views

### Why can small LEDs only conduct ~20mA and a 1N4001 can conduct 1A?

I know red LEDs have a higher forward voltage drop than a silicon diode; this leads to about 2.6x more power dissipation at a given current and so 2.6x less current rating, but 20mA is way less than ...
911 views

### LED modeling with Shockley diode equation

I'm working on a project where I need to model the voltage/current relationship of various LEDs. I'm wondering what values I would need to use for the saturation current in the Shockley diode ...
31k views

### What is “forward” and “reverse” voltage when working with diodes?

What is the difference between "forward" and "reverse" voltages when working with diodes and LED's? I realize this question is answered elsewhere on the interwebs such as wikipedia, but I am looking ...
9k views

### How do I model an LED with SPICE?

What diode modifiers are used in practice to model LEDs with SPICE (Berkeley v.3f5)? These are available to me: ...