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LEDs do have some internal incremental resistance so the capacitor will have some effect. I ran a simulation to find out, but I had to change "CX" to about 0.47 µF (not "472", i.e. 4.7 nF, as shown in the original schematic, which I assume is a typo) to get significant LED current. LTSpice doesn't have a great range of LEDs. The LEDs I used in the simulation, type QTLP690C, appear to be pretty standard red LEDs.`C1 is not necessary, many led displays are multiplexed and have a pulsed supply. If you wish to smooth the current in the leds, then a resistor would be needed to run C1 appreciably above the led voltage.
Agreed!Putting a 5V zener in place of C1 may not work. The supply is current controlled. If the leds need more than 5V, they will not light, if they need less than 5V then the zener does nothing.
The main reason is that only 1/2 of all LEDs would be on per half cycle of the mains sine, thus effectively halfing light output for a given number of LEDs.I do not understand why the components D5, D6, D7, D8 are not fully erased/deleted from the circuit; and make D1, D2, D3, D4 the LEDs instead.
This is required by the simulator as 0V reference point. It has no practical relevance. But voltages are differences in potential energy and since there is no absolute 0V reference potential, you need to supply one to the simulator. You can place the GND symbol (almost) anywhere in the circuit.And, why is there a grounding symbol ?
What Harald said. Each LED would only illuminate for a maximum of half the time.I do not understand why the components D5, D6, D7, D8 are not fully erased/deleted from the circuit; and make D1, D2, D3, D4 the LEDs instead.
I used 0.47 µF and got a mean LED current of 28.4 mA. That's too high for 20 mA LEDs but the application is lighting, not indication, so LEDs are normally rated for more than 20 mA.Same for the original poster circuit, no C1 either. And 1 uF may be too much for 230VAC on ~20mA LEDs. I would use 0.1 to 0.33 uF
As Harald said, it's only needed for LTSpice, the simulator. Without it, LTSpice goes haywire and throws up all sorts of crazy errors! It definitely does not correspond to mains earth! It's not actually a ground symbol anyway.And, why is there a grounding symbol ?
Still can't see it. Save the image to your hard disk then upload it as an attachment to your post.this is the standard mobile phone charger circuit. is this technology differ from above method? is there a transformer or chock or inductor in yellow colored component ?