Police Lights
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The numbers I am giving are on average and not exact.
Orange Led = 2v drop, 25mA (.025)
You are using 3v so subtract 2v from 3v which gives you 1v.
Now to find the resistor value divide 1v by your Led current of 25mA or .025 = 40R resistor - You wont find the 40R so use a 39R that's the closest.
Something to consider...... If you wire these in series you only need one resistor but with only a 3v supply you will have dim Led's just by adding a couple together. You can wire them in parallel but then you need 1 resistor for each Led.
The answer to the second part is yes you can flash the white light but could you give more detail such as the size of the Led's 3mm, 5mm, 10mm.... Do you have the part numbers for the Leds? That way we could look up the datasheets and get exact numbers. If you could please draw a simple schematic or picture of some sort showing exactly what you are doing and with how many total Led's.
George
Orange Led = 2v drop, 25mA (.025)
You are using 3v so subtract 2v from 3v which gives you 1v.
Now to find the resistor value divide 1v by your Led current of 25mA or .025 = 40R resistor - You wont find the 40R so use a 39R that's the closest.
Something to consider...... If you wire these in series you only need one resistor but with only a 3v supply you will have dim Led's just by adding a couple together. You can wire them in parallel but then you need 1 resistor for each Led.
The answer to the second part is yes you can flash the white light but could you give more detail such as the size of the Led's 3mm, 5mm, 10mm.... Do you have the part numbers for the Leds? That way we could look up the datasheets and get exact numbers. If you could please draw a simple schematic or picture of some sort showing exactly what you are doing and with how many total Led's.
George
Last edited:
Hi George,
Thank you for your help
Instead of orange LEDs im going to use yellow LEDs. And also instead of 3V im going to use 9V, like in the wiring diagram.
Heres a wiring diagram i tought maybe worked, i have left all the resistors empty so if you could tell what kind of resistor would go where on the empty spaces. On the LEDs manufactourer page they say that the yellow 5 mm LED uses 2.5V, and the white is 5mm Super bright 3.5V
Thank you wery much
Casper
Thank you for your help
Instead of orange LEDs im going to use yellow LEDs. And also instead of 3V im going to use 9V, like in the wiring diagram.
Heres a wiring diagram i tought maybe worked, i have left all the resistors empty so if you could tell what kind of resistor would go where on the empty spaces. On the LEDs manufactourer page they say that the yellow 5 mm LED uses 2.5V, and the white is 5mm Super bright 3.5V
Thank you wery much
Casper
Hi i have successfully made the circuit on a breadboard but when i completed the transfer on to the perf board only one set of leds lit up.
here is the pcb design that i have check over can you please verify that is correct so that i can start again View attachment 145
here is the pcb design that i have check over can you please verify that is correct so that i can start again View attachment 145
Its hard to tell whats conected to whaton this pic, but on your board double check those diodes polarity and transistor conections. I check every lead and make sure it goes where it needs to before I print my circuit. Then check again after etching/before soldering. Its super easy to over look simple mistake ...
my brother is rural route postal carrier and im trying to make some caution lights for his Jeep.is there a schematic for this that runs off 12v and runs something like these lights (I'm thinking maybe 6 to 8 of them)?Also i plan to have some red lights that do same strobe when he uses his brakes. I'm very new to this but look forward to the challenge of building the circuit.any advise on where to look on how to learn this kind of stuff would be appreciated.
I built this circuit & it worked the first time. Used 2N3904 transistors & four blue LEDs, so I replaced the 470-ohm resistors on the latter two w/ 4.7k's (they were too bright). But what is the purpose of 470's going to ground off the bases of the transistors? I mean, the circuit seems to work fine whether they're present or not. Also, do you make/sell PCB's for any of these circuits?