I need to replace bulb that's inside of a button for car window.
The bulb is 12V T1 1/4 80mA and because it's a bit difficult to find it in a store, I decided to put orange LED 2.5V 50mA.
Is it safe to put LED with resistor 1/4 watts 270 ohms?
Ignoring the LED voltage, the resistor would dissipate (V^2 / R) almost 1W at 15V, which is what the electrical system may run at from the alternator.
You need a much higher power resistor (or combination of resistors), or use an ultra-bright LED that will give adequate illumination at rather lower current, so you can use a higher value resistor.
Edit:
Or would one of these be a drop-in replacement for the original bulb?
50 mA through an LED is a lot. That will be far brighter than the original lamp. I would start at 10 mA or less, with 1200 Ohms, and then you will only get around 130 mW in the resistor.
U ovoj potkategoriji možete pronaći sijalice čiji se napon kreće od 3V do 12V kao i tinjalice različitih boja čiji se napon kreće od 12V do 220V, dok im je prečnik ugradnog otvora: Ø10.00mm i Ø12.00mm u zavisnosti od tipa tinjalice.
www.mikroprinc.com
I guess I could use 12V, 50mA, 0.60W without resistor?
Merna i test oprema, lemna oprema i pribor, elektronske i elektromehaničke komponente, poluprovodnici, napajanje, programatori, računarska i telekomunikaciona opreama, najveći izbor kvalitetnih alata i opreme.
Just use an LED of the right colour that fits in the space, get the connections the right way round, fit a resistor in series, make sure that the current rating of the LED is not exceeded, and that the power rating of the resistor isn't exceeded.
Just use an LED of the right colour that fits in the space, get the connections the right way round, fit a resistor in series, make sure that the current rating of the LED is not exceeded, and that the power rating of the resistor isn't exceeded.
Is there enough room in that housing to use eg. three 3mm LEDs in series, such as with the leads on each bent 90' out, trimmed and soldered directly to each other?
That gives three times the light for a given current and reduces the voltage across the series resistor, so that is producing less heat.
Merna i test oprema, lemna oprema i pribor, elektronske i elektromehaničke komponente, poluprovodnici, napajanje, programatori, računarska i telekomunikaciona opreama, najveći izbor kvalitetnih alata i opreme.
Is there enough room in that housing to use eg. three 3mm LEDs in series, such as with the leads on each bent 90' out, trimmed and soldered directly to each other?
That gives three times the light for a given current and reduces the voltage across the series resistor, so that is producing less heat.
I have replaced bulbs in three of four buttons with 12V, 50mA, 0.60W.
Fourth button bulb have to be desoldered/soldered but I am not sure how to pull out circuit board out. It doesn't lift up, it seems like it's soldered inside to something and it holds it back.
I am not sure that I can lift it up if I desolder all leads.
That's commonly called a "grain of wheat" lamp. it's a filament lamp. Essentially what you have.
It depends on which way the light has to face. From your pic, it seems it has to face toward the paper. the lens will mess it up. So, yellow LED with yellow lens. there might be some right angle LEDs or axiel leds that can work. Just size R correctly.
examples:
Series wiring would not be too bad, just alternate them.