Electrical Engineering

Questions tagged [transformerless]

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41 questions
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-1
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2answers
102 views

How to obtain 360vdc from 240vac for audio use without a transformer?

I'm in the process of creating a tube guitar amplifier with an output power of ~6w (fender vibrochamp AA764) which requires the use of 360-400vdc. How could I obtain such a voltage from mains without ...
0
votes
1answer
62 views

+/- 96 V transformer less power supply design

I know this is a dangerous practice, but obtaining a transformer to make a vacuum tube power supply in my country is prohibitively expensive. So i have to go for transformer less psu. I am just making ...
1
vote
1answer
48 views

Modify Transformerless Power Supplies

Based on this article: https://hackaday.com/2017/04/04/the-shocking-truth-about-transformerless-power-supplies/ I have some rf wireless plug outless which use transformerless power supply. I would ...
-1
votes
2answers
79 views

Prevent transformerless powerless supply going full voltage on O/P in case of open circuit

I would like to automate two of my lights using Nodemcu and a 5 V relay board. I am planning to power the relay and Nodemcu with a transformerless power supply. Is there a way to prevent full voltage ...
-2
votes
1answer
105 views

What resister I want to use to drop voltage for LED? [duplicate]

I am going to connect 10 led in series without a transformer. Now I want to know the value of resister to connect 10 led in series and please give the calculation method thank you.
0
votes
1answer
196 views

What types of signals can a dynamic microphone generate?

And what design generates what type of signal property? For example there are dynamic mics with or without output transformers. Do they differ in the type of signal outputted? Do most dynamics ...
7
votes
7answers
5k views

Transformerless power supply

I'm looking for building a power supply circuit that will convert 230VAC to 5VDC in order to power up an Atmega328P. I also want this to be as small as possible. I know a transformer is one option ...
-3
votes
1answer
93 views

Transformerless supply [closed]

I am desigining a transformerless supply with two cap in series .if I measure the voltage across 1st cap it is 80 volts and same for other but net voltage measure across these two caps are 240 How and ...
-1
votes
3answers
312 views

2kV AC step down to 5v without using transformer [closed]

I'm doing an industrial project, i need to step down the high voltage of 2kV to 5V, is it possible to step down to around 5V without transformer, is there any other alternatives? please suggest me :)
1
vote
2answers
1k views

ATtiny13a capacitive power supply

I would like to power my Attiny13a MCU with a transformerless capacitive power supply. The MCU itself needs only a few milli amps and it will drive 2 LEDs at 15mA each through it's digital pins. So I ...
-2
votes
2answers
156 views

Capacitive Power Supply Zener Resistance

I am designing a Capacitive power supply, I found someone who did the circuit shown in the figure. I don't know what is the usage of the 47 ohm resistor in series with the Zener diode (12V MELF ...
0
votes
2answers
394 views

Polypropylene capacitor power supply [duplicate]

I found some articles talking about transformerless power supplies, and I have uploaded the schematic of such a circuit. Does anybody have an idea about the pros and cons of such a power supply? Also ...
-4
votes
2answers
649 views

LM317 output voltage to 0 V with transformerless negative voltage created through a buck converter

I try to construct a shut down pin or a feature which can set the output of LM317 or LM78XX with negative voltage that is created through a transformerless buck converter. A buck converter having ...
0
votes
1answer
162 views

Identifying unknown components in transformerless power supply

So my dad found one of these voltage converters lying around. I was quite curious what components it had as it is very lightweight (transformerless) and boasts a good 1600W @ 110vac (14.5A) on the ...
0
votes
0answers
373 views

Safety of zener diode based non isolated power supplies

Are the following zener diode based non isolated power supplies safe to use with a touch based application? I would assume, the circuits are safe if they completely sealed (including the touchpad). ...
1
vote
1answer
184 views

Capacitive power supply - Bleeding resistor reliability considerations

We are using a capacitive power supply for one of our applications. The X2 capacitor (330nF in this case) provides good reliability with respect to failing safely/open and good over-voltage ...
19
votes
8answers
4k views

Two resistors in series

I know the summation equation for two or more resistors in parallel or series, and I know two parallel resistors will give more power. But sometimes I saw some circuits that used two resistors in ...
0
votes
2answers
941 views

Protect my circuit from overvoltage on AC line

I used this link to generate a 5VDC (1A) from the 220Vac power source, the circuit itself works perfectly fine but i want to make sure that the overvoltage on the AC line won't damage my board. I ...
2
votes
3answers
2k views

Designing small size AC/DC to provide 3.3 V for MCU [closed]

I have designed ESP8266 based light switch, that is controllable via web page or a push button. Light is being switched with use of Triac (TIC206) through optocoupler (MOC3041). Prototype works as ...
-13
votes
2answers
353 views

Will this laptop charger work?

My laptop adapter just broke out, so I decided to make a simple adapter of my own but I would like someone to check the circuit diagram and tell me if it would work or not??
4
votes
2answers
528 views

Reducing volume for a split-phase 230VAC@60Hz sealed power supply providing 5VDC@50mA

I'm a hobbyist interested in re-designing and implementing a DC power supply providing a \$+5V_{DC}\pm 200mV\$ output with a current compliance of \$50mA\$ (I could live with \$30mA\$ successfully) ...
0
votes
1answer
2k views

How to calculate output voltage of a non polarized capacitor?

How to calculate output voltage of non polarized x-rated capacitor (230VAC 5A 50/60Hz)? (which depends on input voltage) as like as the calculation of output current here tutorial table here tested ...
2
votes
2answers
1k views

Isolation of the transformerless power supply

One of the disadvantages of transformerless power supply is the isolation problem because of the absence of the transformer. My question here is : Doesn't the capacitor in series at the input do the ...
0
votes
1answer
208 views

Can tranformerless inverter topology be used in UPS with a regular battery (12V 7Ah)?

While searching for transformerless inverters in the IEEE site, most of them seem to be about grid connected Photovoltaic inverters. Removing transformers will increase the efficiency at the cost of ...
1
vote
0answers
187 views

Transformerless Realtime Clock Issue

I have an issue with designing a Real Time Clock by using Transformerless power supply. I don't use RTC IC but I use Microchip PIC instead and 32kHz clock. I use battery of 3.3V for backup supply. The ...
0
votes
1answer
2k views

Transformerless Power Supply High Current

Is there any way for Transformerless Power Supply to output a High Current like 10A to 15A at 12V to 24V. I found highest of 500mA current output for Transformerless Capacitor Power Supply. I wanna ...
0
votes
1answer
3k views

Transformerless power Supply - 24VDC, 120V AC and 230V AC

I want to know if it is possible to design a power supply for a circuit that can operate from DC and AC using the same input terminals. Thus, the output should be xxV DC (5-24 or whatever is decided ...
0
votes
1answer
424 views

Transformerless rectification is giving out AC component [duplicate]

I want to convert 240V AC 50hz to 12V DC without transformer.I want the output (12V) to drive 25 white LEDs.The circuit is giving an output of ~14V DC.But the problem is that it is also giving out ~...
0
votes
1answer
956 views

Capacitive transformerless power supply, AC polarity problem

I have implemented a "Capacitive transformerless power supply" to control a microcontroller-based circuit that contains capacitive touch sensors, and I had an "AC polarity problem" Surprisingly, the ...
-2
votes
2answers
1k views

how to design transformer less power supply? [closed]

I want to desgin a 5V,0.5A transformerless supply (minimum components) for mains 100-260Vrms, 45-65Hz? I found several ways to do it which are mentioned below 1. resistive power supply - Microchip ...
0
votes
1answer
194 views

How can I make a POWER-LED Lamp?

What is the best way to light 10 POWER-LEDs with AC mains (220V)? (I want to make an LED lamp.) Here is more info: I have 10 of these POWER-LEDs: Product Chip: 40x40 mil Chip Brand: EVERLIGHT-...
0
votes
2answers
9k views

Use of transformer in arc welding

Why transformer is used in arc welding and what will happen when anyone touch the electrode at the time of welding?
3
votes
4answers
5k views

Surface mount transformerless 230v to 3.3v on a small board

I am trying to design a 3.3V mains power supply to go on a PCB approximately 50x25mm in size (this will include other functions too!). I've come across the Supertex SR086, which is almost perfect, ...
1
vote
0answers
878 views

Split-phase 230VAC transformerless capacitive power supply for 5V@30mA regulated output — series cap?

I'm a hobbyist developing a hybrid power switch (electromagnetic + solid state) for a resistive electric stove (8kW max) top. I have a profoundly autistic, disabled adult in the house and I need a ...
3
votes
2answers
2k views

Designing a Transformerless power supply

I am working on a transformerless PSU for maiking a 3nos.x3 watt led, each having forward voltage around 3.6v and current around 650-700ma. I have worked on this kind of circuit: I guess a 1uf ...
0
votes
1answer
310 views

Transformerless inverter from 20*12V batteries

Is it possible to convert 240VDC from 20*12V batteries to 180VAC-240VAC pure Sine Wave? i have an idea using H-Bridge mosfet drivers....But i have seen on web that 350Vdc is must to convert it to ...
2
votes
3answers
2k views

Power Supply Design

I just let the smoke out of my testing setup. I designed and built a simple power supply using this guide. I built a capacitive power supply with a bridge rectifier and a final 3.3VDC voltage ...
8
votes
1answer
2k views

Understanding CS5463's basic circuit power supply

I'm trying to put the CS5463 chip functional using the example circuitry on page 41 of the datasheet (attached bellow): Right now, I'm working on the top part of the circuit, which is the IC power ...
6
votes
1answer
2k views

How to calculate the zero crossing offset in a capacitive transformerless power supply

I'm working on a circuit powered by a capacitive transformerless power supply, that is a microcontroller based triac-switching project for resistive loads. I've taken the basic design of the power ...
6
votes
1answer
3k views

Requirement to display 3 mm LED by 220 V AC supply

I want to power a single 3 mm LED by a 220V AC source. For this I think I need one LED, one resistor and one capacitor. I don't know the needed resistor value and circuit diagram. The circuit also ...
25
votes
6answers
31k views

How efficient is a capacitive power supply?

Something like this Falstad sim version of it (I'm tired, I keep making mistakes, so please excuse me for the second time.) Now these are not very safe PSU's, due to the lack of isolation. But in ...