Questions tagged [transformerless]

Transformerless power supplies produce a low voltage from AC mains without using any kind of transformer and without providing any safety isolation.

Filter by
Sorted by
Tagged with
-1 votes
4 answers
210 views

6 amperes in transformerless power supply [closed]

Can we get more than 5 to 6 amperes in a transformerless power supply by choosing these values: Don't take the values in drawing as exact. C bunch in parallel could be polarized motor cap (100 uF/...
Hars's user avatar
  • 171
0 votes
0 answers
72 views

Glue gun series dropping capacitor

I have a 40 W on label glue gun for 230 V socket, PTC element could be 20 W as some manufacturers use 20 W instead and label it as 40W . I want to add a voltage dropping capacitor to increase its ...
Hars's user avatar
  • 171
0 votes
1 answer
165 views

What’s the explanation on why the outlets wires are on the same coils?

Working on fixing a once upon a time good soldering station so I thought. Inside the soldering station there’s two transformers, first one for the soldering iron that has an primary of 115 V and ...
Jake Fanthorp's user avatar
0 votes
0 answers
58 views

Why does my power supply circuit not function correctly when connected to a load circuit?

My transformerless power supply on the left side of the voltmeter outputs 24V/12V until I connect it to my load circuit on the right. The voltage coming out becomes and stays at 1.5 V at most and I ...
batekoi's user avatar
1 vote
4 answers
273 views

Do voltage multiplier circuits and transformerless power supplies have functional similarity? [closed]

I saw diagrams of voltage multipliers like in the picture below. To my understanding, it seems like they have the same function as transformerless but the use of a voltage multiplier is to increase ...
user avatar
3 votes
3 answers
227 views

Confusion about DC output voltage in this circuit

I am building a transformerless power supply to power 60 RGB color changing 2 pin LEDs in series from 230 VAC mains. These LEDs need DC to function properly. In the circuit below, I understand that ...
Sumedik's user avatar
  • 31
7 votes
5 answers
1k views

Converting 24 VAC to 5 VDC with small output current

I have a transformer which outputs 0.33 A at 24 VAC. I would like to rectify this down to 5 VDC and minimal current, 50 mA being the maximum. I came across the following schematic which seems to be ...
jhorv's user avatar
  • 85
-2 votes
1 answer
185 views

Is it possible to make a 220 VAC to 12 VDC, 5 A transformerless power supply?

I need to make a power supply that takes 220 VAC and outputs 12 VDC and can handle 5 A. Where I live there are no flyback transformers for sale and importing them is a big hassle. I have some ideas ...
AhmedH2O's user avatar
  • 287
1 vote
1 answer
488 views

Simple transformerless 3.7VDC to 220VAC [closed]

I am looking for a circuit design that could be capable of inverting 3.7VDC to 220 VAC. The maximum current draw is below 50 milliamps, and this circuit shouldn't have problem like voltage drop as ...
M A K's user avatar
  • 79
0 votes
0 answers
53 views

Problem with how circuit work in china transformerless voltage sensor pilot lamp

I want to actually understand the circuit completely but for the specific, i want to really understand how this circuit can actually output ac voltage in OUTPUT_SENSOR point and the waveform is ...
Dimas Arjuna Nusantara's user avatar
0 votes
3 answers
245 views

How does this "single-ended push-pull with transformerless driver" work?

I'm studying the circuit block below in an Italian textbook, "Dispositivi e circuiti elettronici", by M. Gasparini, D. Mirri. The circuit is called "single-ended push-pull with ...
barrow's user avatar
  • 163
1 vote
4 answers
513 views

An inverter without a transformer?

I am trying to build an inverter without a transformer. I want to use a 12 V battery connected to a boost converter which will boost the 12 V to 120 V, then simply attach an H-bridge to the 120 V ...
BELSmith's user avatar
  • 146
0 votes
1 answer
417 views

Rectified 230VAC to 24VDC

I am building a simple motor control application, driving a series wound motor that runs on rectified 230VAC. Originally, it was controlled by a pendant switch connected to a 7 pin connector. The idea ...
Guillermo Oliver's user avatar
0 votes
0 answers
173 views

How to build a simple 12VDC-12VAC transformerless inverter using transistor

I am looking for a circuit diagram or an explanation on how to build a 12VDC-12VAC inverter circuit without using a transformer or an inductor of any kind. I want this circuit to be as simple as ...
Milton L. Rowlands's user avatar
-2 votes
2 answers
518 views

Can we make a transformerless 220V to 12V converter without a Zener doide?

I saw many circuits have a Zener diode, but a guy from Youtube lighted up a 12V LED without a 12V Zener diode in the cicuit. How is that?
Tubrag's user avatar
  • 169
0 votes
3 answers
963 views

Capacitive dropper power supply for LED - zener/decoupling capacitor?

Let's say you have a standard capacitive dropper power supply like the following (from Wikipedia): I understand that these work well for driving LEDs since they act like a constant current source. I ...
flashbang's user avatar
1 vote
2 answers
542 views

Capacitor protection in transformerless power supply

I am designing a capacitor based transformerless power supply for a WiFi-based device which will be on for 24x7, with an input of 230VAC at 50Hz. For almost 80% of the time, the device would consume ...
Chaitannya's user avatar
1 vote
1 answer
374 views

Voltage dropping capacitor doesn't drop the voltage?

I am going to make a transformerless power supply. Here I am using a 105J 400V polyester capacitor to drop the voltage. I connected the capacitor and AC main in series, but when I measure the voltage ...
user238870's user avatar
0 votes
0 answers
62 views

Is it possible to connect a switching buck converter to a simple transformerless power supply?

Many cap based transformerless power supplies intended to use with 5V circuits, use a 5.6 zener diode to regulate ouput voltage. I'm using below circuit and the calculator here [which is based on the ...
Tirdad Sadri Nejad's user avatar
1 vote
1 answer
90 views

Why using capacitor in transformer less ac to dc converter

I saw many transformer-less power supplies using capacitive resistance of a capacitor. But I don't know exactly what the reasons are for using capacitors instead of normal resistors . I guess two ...
MohammadAli Zeraatkar's user avatar
0 votes
1 answer
454 views

What kind of power supply is best for IoT application?

I am trying to make some IoT devices to fit in wall outlet. There is an issue with power supply. I have to feed my circuits from 220V outlet and there is a limitation in size. I tried to use some HLK ...
Mehdi Maazi's user avatar
0 votes
2 answers
627 views

6.2 V zener shows lower voltage (Multisim)

I have this circuit with a 1N4735A 6.2 V zener diode. I am trying to figure out why am I measuring 5.1 V across it. The circuit is a transformerless power supply with more or less 60 mA of maximum ...
Gabi M's user avatar
  • 1
2 votes
2 answers
659 views

Capacitor Vrms vs Vpeak Rating in Transformerless Supply

Why is it that when calculating for voltage across the capacitor in transformerless power supply we need to use peak voltage not RMS voltage value. To be clear I am referring to the rating of C1 in ...
user595628's user avatar
0 votes
0 answers
136 views

Capacitive Power Supply Torch

I'm an amateur at electronics circuitry and concepts. I have designed a simple capacitive power supply using few web images and brief lessons. I understand that this type of transformerless power ...
putu06's user avatar
  • 91
2 votes
1 answer
594 views

Adding ethernet jack and transformer to device designed without one

I'm attempting to add an RJ45 Ethernet jack to a commercial device without one by replacing an embedded WiFi module, which, according to its datasheet, is connected to the rest of the system as ...
DodoDude700's user avatar
-1 votes
1 answer
285 views

Transformer less Power supply's waveform is Noisy

Hi I want to measure the mains voltage using transformerless power supply. the output of the supply is fed to an optocoupler and later read by a microcontroller. The problem i am having is that the ...
Farvez Farook's user avatar
0 votes
5 answers
1k views

Resistor & capacitor are getting too hot

I made a transformarless power supply with capacitor. When i connect it on ac, it light the leds. But after some second the 100ohm resistor and 470uf capacitor get too hot. Its too hot that i could ...
Suny's user avatar
  • 3
-1 votes
2 answers
145 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 ...
Calin Ionut's user avatar
0 votes
1 answer
147 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 ...
Ashok Das's user avatar
1 vote
1 answer
481 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 ...
user avatar
-1 votes
2 answers
92 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 ...
user avatar
-2 votes
1 answer
118 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.
Mathu Suthan's user avatar
0 votes
1 answer
367 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 ...
JAudio's user avatar
  • 3
9 votes
7 answers
7k 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 ...
Danaro's user avatar
  • 123
-3 votes
1 answer
110 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 ...
Jasleen Kaur's user avatar
-1 votes
3 answers
417 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 :)
Dexter's user avatar
  • 9
2 votes
2 answers
4k 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 ...
Kokachi's user avatar
  • 678
-2 votes
2 answers
219 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 ...
Ashraf Almubarak's user avatar
0 votes
2 answers
1k 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 ...
ahm_zahran's user avatar
-4 votes
2 answers
1k 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 ...
rxpu's user avatar
  • 1
1 vote
1 answer
236 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 ...
illustrious18's user avatar
1 vote
1 answer
982 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). ...
someonr's user avatar
  • 305
1 vote
1 answer
319 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 ...
Rev's user avatar
  • 10k
21 votes
8 answers
5k 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 ...
M.A.K's user avatar
  • 1,838
0 votes
2 answers
2k views

TVS selection guidance to protect against 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 ...
Mehdi Hafezi's user avatar
4 votes
3 answers
5k 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 ...
Marko's user avatar
  • 181
6 votes
2 answers
1k 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) ...
jonk's user avatar
  • 77.4k
0 votes
1 answer
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 ...
Devon Ravihansa's user avatar
2 votes
2 answers
2k 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 ...
iMohaned's user avatar
  • 1,491
0 votes
1 answer
270 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 ...
Mathav Raj's user avatar