Timeline for How to calculate maximum amount of bulbs I can connect in parallel to match design specification of 1.5 A?
Current License: CC BY-SA 4.0
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| Feb 14, 2019 at 10:01 | comment | added | Rohat Kılıç | ... As you might know, a capacitor has nearly zero resistance when it's empty. As the voltage across the capacitor increases, the resistance reaches to nearly infinity. Thus, when you first apply the voltage, the source will see nearly zero resistance (because of empty capacitors). It's not easy to calculate, but you can measure it with a relatively low resistor and oscilloscope. PS: In my LED bulb designs, I always put a series 10R resistor to limit the inrush current so that any fast-acting fuses don't blow. Your loads may have those resistors inside as well. | |
| Feb 14, 2019 at 9:58 | comment | added | Rohat Kılıç | @CcoderBeginner Well it totally depends on the loads. For example, if the load was an incandescent bulb then the inrush current would be the RMS line voltage (\$V_L\$) over the cold resistance of a bulb (\$R_{cold}\$): \$I_n = V_L / R_{cold}\$. (If more than one bulb were connected in parallel then the total load resistance would be \$R_{CX} = R_{cold} / numBulbs\$). For LED bulbs, since they have a bridge rectifier plus a big reservoir capacitor, the inrush current totally depends on that capacitor. ... | |
| Feb 14, 2019 at 9:21 | comment | added | CcoderBeginner | If you don't mind explaining to me how i can calculate the inrush current for this example to be able to reach a safe conclusion for similar scenarios in the future? | |
| Nov 11, 2018 at 16:20 | comment | added | Rohat Kılıç | @CcoderBeginner thanks for your kind words. About your question: Please read carefully. When it comes to 230V you should take a lot of things into account. If you connect 41 bulbs in parallel then the inrush current can be 200 Amperes or even 500 Amperes (not milli Amperes). Connecting 10 bulbs in parallel that I've talked about is just about a fairly estimation for safety. | |
| Nov 11, 2018 at 6:25 | vote | accept | CcoderBeginner | ||
| Nov 11, 2018 at 6:22 | comment | added | CcoderBeginner | That is simply an AMAZING explanation. You paved my way for an unexplored part of my circuitry analysis. Thank you so much for that wonderful explanation. Regarding the 200mA you expect that as soon as they turn on each bulb willl draw that current and thus 1.5/0.2 = (7.5) and thats where the 10 bulbs come from? | |
| Nov 8, 2018 at 13:00 | history | answered | Rohat Kılıç | CC BY-SA 4.0 |