If i use the higher UF capacitor then reactance of the capacitor becomes low and causes higher current to flow through it. Isn't that make any major change in the circuit? in that case is our circuit operate as per our requirement?Mark veniaminavich said:
The smoothing capacitance is determined by the maximum load current and the tolerable ripple voltage. There is a formula for this.seemasdawange said:
A larger capacitance may cause a larger inrush current at switch-on. This can put a strain on the rectifiers, and the fuse—and also the on/off switch.
Thanks dats what I'm expecting.NascentOxygen said:
Can you post a copy of your schematic? That would help us to answer any questions that you have. There are lots of ways of making a transformerless power supply. Use the UPLOAD button to attach a copy of your schematic to a post. Thanks.seemasdawange said:
berkeman said:Can you post a copy of your schematic? That would help us to answer any questions that you have. There are lots of ways of making a transformerless power supply. Use the UPLOAD button to attach a copy of your schematic to a post. Thanks.
okay. so what should i do? remove it from series? actually this resister also has power loss in form of heatNascentOxygen said:
To limit the current. if voltage goes too high in that case it may protect capacitor by limiting the currentNascentOxygen said:
Yikes. I see several problems here. Where did you get this circuit? Can you link to the original source? Overall, this circuit makes no sense, IMO.seemasdawange said:
No I tried to design it by myself. i read from some source to add series resistance there http://www.designercircuits.com/DesignNote1a.pdf check this pdf u may get the answer.berkeman said:
yes of course. my load is a relay of 12 Volts and have power ratings of 0.36Watts. that means load current is 30mAmpsNascentOxygen said:
check this image. and look at the output waveform.seemasdawange said:
Hmm, u r ryt. can u suggest any module den?NascentOxygen said:
You may not understood previous diagram as there was transistor and battery of 12Volt shown. the simplified diagram is here. you can check this. is that ok? or still have some problems?berkeman said:
Ok ThanxNascentOxygen said:
No, it still has errors and makes no sense. Why are you insisting on putting a capacitor in series with the AC Mains input? I can think of no reason in this circuit to do that. And you appear now to have deleted the input storage capacitor. Why?seemasdawange said:
berkeman said:
The capacitor is there as a low-heat (i.e., low energy-loss) voltage-dropping impedance. This is standard design of this type of low-power transformerless power supply. A voltage-dropping resistor can be used instead, but this is substituting one problem with another: dealing with the heat that resistor produces.berkeman said:
Thanks NO. At my work, we actually publish a reference design for low-power non-isolated applications that uses capacitor isolation, so I probably should have recognized that. Still, the design seems to have some issues. I wonder if the OP understands what they are trying to do. It would be good to see some specifications for the design from them...NascentOxygen said:
NascentOxygen said:
A transformerless power supply is a type of power supply that does not use a traditional transformer to convert high voltage AC power to low voltage DC power. Instead, it uses electronic components such as capacitors, resistors, and diodes to step down the voltage and regulate the output.
Some advantages of using a transformerless power supply include smaller size, lower weight, and lower cost compared to traditional power supplies. They also have higher efficiency and can be designed to have a longer lifespan.
Yes, there are potential safety concerns with transformerless power supplies. Since they do not have a transformer to isolate the output from the AC mains, there is a risk of electrical shock if not designed and installed properly. It is important to follow safety guidelines and regulations when using transformerless power supplies.
No, not all electronic devices can be powered by a transformerless power supply. They are best suited for low power applications such as small electronic devices like cell phones, laptops, and LED lights. High power devices typically require a traditional transformer-based power supply for safety and efficiency reasons.
The appropriate transformerless power supply for your electronic device will depend on the power requirements of the device. You will need to consider the input voltage and current requirements of the device and choose a power supply that can provide a stable output within those specifications. It is recommended to consult a professional or refer to the device's manual for guidance on selecting a suitable power supply.