power supply

tubeguy

Joined Nov 3, 2012
1,157
I think you'll be disappointed.

(referring to #19, which has no current limiting on the LEDs. Poof.)
@Zanac-X I mentioned this in post #7 also. I provided a formula to calculate the resistor..

There is a lot of info provided for you. It might be good to review the post's, but keep at it !!!
Lot's of good people here willing to help !!! ;)
 
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Thread Starter

Zanac-X

Joined Dec 23, 2011
51
wayneh : i know, i didnt say im going to copy it i just said im going to use it,referring to the max1044 as the main provider of +ve and -ve leads instead of using the previous circuit :)

tubeguy :

1- you must add current limiting resistors in series with each LED.

i know that im just nerrowing the subject to just the power supply, not how to deal with the load.

2- Hobby LED'S typically have a Vf (forward voltage) of ~ 2 to 3.5 volts and need sometimes only a few milli-amps to light up. Voltage above the Vf results in increased current to the point where you will burn out components.

i actually have a list of all the voltages and currents of all the colors of LEDs,so i know all of this.

3-EDIT: Simulators aren't very good at simulating smoke.

actually circuit wizard and other good simulators provide what is called "explosion simulation" and that is for a given properties for all the components it can simulate it as in real life with explosion of that component if limits exceeded.

4-Calculate resistor using Ohms law:

i've done a project of lighting colored letters (ZANAC-X & GOGO-GX) made out of LEDs (1027 i think) using 24v 1 amp DC input and that is the only law used in this circuit.

what i want to say is that i thank you for your time but its not really what im asking for so im sorry if im troubling you in any way

ScottWang : well i dont know what to say, that actually covers it all basically you have just done my homework thanks :)
 

WBahn

Joined Mar 31, 2012
29,976
Part of the problem is that what you really want is not at all clear and seems to be a constantly moving target.

As best I can tell right now, you want a circuit that will let you identify whether a BJT is NPN or PNP and whether it is working properly. You say you need a single circuit and not a different circuit for each type. Well, the basically rules out using a circuit with a bunch of jumpers or switches since, if that is allowed, you can just make a circuit for each type and use the switches to select which circuit is in use.

The goal of making a circuit that can identify whether it is PNP or NPN is pretty well specified. But what is meant by testing to see if it "works properly". For the purpose of your test, what constitutes working properly?
 
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