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-1
votes
1answer
38 views

Output voltage limiter for transformator [closed]

I wanted to add a voltage limiter for a flyback circuit. I simulated with http://www.falstad.com/circuit/ and this is the current circuit: http://pastebin.com/fbuSuMYX. I was thinking to add a zener ...
0
votes
1answer
27 views

ZVS transformer output voltage [closed]

I was running a simulation with: http://www.falstad.com/circuit, this is my circuit: http://pastebin.com/QKZ6gevy. When I add a capacity, the voltage is not going beyond 50-60V at the end of the ...
1
vote
1answer
58 views

ATtiny85 absolute ratings for outputs?

The ATtiny85 datasheet specifies an absolute maximum negative voltage for any pin of -0.5 volts relative to ground. Consider this partial schematic: MOSI and MISO are the respective ATtiny85 pins ...
0
votes
1answer
40 views

Function of UCC2813-1 in flyback converter

I am studying a design of a fly back DC-DC converter. It is based on TL431 voltage regulator with PC817 opto-coupler. I heard that it is a popular design used. Switching PWM pulses are generated ...
0
votes
1answer
40 views

Inductances in flyback transformer

I am simulating flyback dc-dc converter in multisim software tool .. I want to know the difference betweem primary inductance and magnetising inductance , also secondary leakage inductance?
2
votes
1answer
65 views

Catch diodes in switch mode power

I am wondering about catch diodes in the context of switching power supplies. I have read all the books that are the norm in designing a SMPS, but all of them don't or barely touch the subject. My ...
0
votes
3answers
95 views

1:1 and flyback transformer at low frequency and high temperature

I am designing a circuit in that I need 1:1 and fly-back transformers at low frequency (0-100kHz) and high temperature. Can anyone help me with these? I am looking for voltage being handled around ...
1
vote
2answers
100 views

What is the reason my ULN2003A overheats?

I'm driving some 12v fan motors from a microcontroller using ULN2003A Darlington array. Both total wattage and per-channel wattage are way below ULN2003a limits. Still, I found that when PWM duty ...
0
votes
1answer
143 views

Flyback NE555N driver and mosfet overheat

I have built a small and very simple flyback SMPS based on NE555N IC. The circuit exactly I did built from is shown below: It works nicely for small loads. However I have some issues with it: ...
0
votes
2answers
155 views

Flyback SMPS Transformer choice

In several projects so far, I have been using old "fashioned" transformer based power supplies. However, this time around I want to use a switching mode power supply. The supply will be used to power ...
1
vote
1answer
54 views

Power supply for a LED driver

I'm working on a project in school were I have the PMP4862 circuit as a reference. Unfortunately the flyback is no longer available. How can I modify the circuit to use available parts? I wonder if ...
1
vote
2answers
172 views

Should a rectifier or TVS diode be used as a flyback diode?

I'm trying to design a circuit for a relay similar to the following (except using SMT components): When I went to Mouser to try to find a suitable SMT diode to use in place of the 1N4001, I noticed ...
5
votes
2answers
905 views

How to choose a flyback diode for a relay?

A diode is put in parallel with a relay coil (with opposite polarity) to prevent damage to other components when the relay is turned off. Here's an example schematic I found online: I'm planning ...
2
votes
3answers
187 views

Is it possible to store flyback voltage in capacitors?

I recently put together a circuit that I use to control an electrical motor. I use an Arduino's PWM through darlington-pair transistors to control the speed of the motor. During construction of this ...
0
votes
1answer
126 views

Where to salvage inductors?

I need a toroidal inductor for my ZVS flyback driver. The value should be between 47uH to 200uH. It should be able to handle 6A. Where can I salvage them from?
2
votes
3answers
186 views

NE555 Flyback Driver MOSFET failiure

simulate this circuit – Schematic created using CircuitLab I made this simple NE555 Flyback driver. I used a 9V Battery to power the NE555 and a 24V 6A power supply to power the flyback. ...
4
votes
2answers
283 views

Flyback diode forward voltage drop

In an ideal flyback diode selection, one would seek a diode which has very large peak forward current capacity (to handle voltage transients without burning out the diode), low forward voltage ...
0
votes
0answers
81 views

How to get better output out of flyback driver?

simulate this circuit – Schematic created using CircuitLab I used this circuit to power my flyback... I used an MJE3055T Power NPN and 10kOhm pot. The flyback is FKD15A001. I used the ...
0
votes
1answer
125 views

IC555 flyback driver troubleshooting

I made a flyback driver which just uses an astable 555 circuit to drive the flyback. The 4 and the 8 pins were connected to the positive rail. 7 pin was connected to the positive rail via a 1K ...
2
votes
1answer
193 views

H-Bridge freewheeling current

I'm building an H-Bridge to drive some motors I have around. I'd like to have a bridge that can be powered by different power sources, for example batteries or atx power supplies interchangeably. ...
2
votes
2answers
207 views

How does a flyback diode work?

In a previous question I posted to the exchange I asked for some instructions on trying to variable speed control a motor. Someone suggested utilizing PWM from my Arduino to open and close a ...
4
votes
2answers
228 views

What are the effective power limitations of the flyback converter topology, and why?

Looking at several different isolated converter topologies, flyback looks like it's the simplest at first glance. There's only one switch, so there's only one driver, which (all other things being ...
0
votes
1answer
745 views

Simulating a Flyback converter using Matlab / Simpowersystems, cannot get it to work, any tips?

I have created a flyback converter model using Simpowersystems in Simulink/Matlab. But it always gives me the wrong answer! I have simulated the same system using PLECS and Simscape/simulink and got ...
5
votes
4answers
3k views

Correct use of Flyback or Snubber diode across Motor or Transistor?

From seeing a few schematics where the flyback or snubber diode has been placed across the transistor C-E terminals (Right Configuration), instead of what I typically seen as the the flyback being ...
4
votes
3answers
364 views

BJT vs MOSFET for very low power flyback converter

I am currently working on a flyback design charging a capacitor in the nF range to 200V from an input voltage of around 1.5V. As the final circuit should be as small as possible, my component choices ...
0
votes
2answers
120 views

Electric vehicle power component selection help

I need your advice on high power device selection. I'm working with a similar application to this schematic, with the descriptions being in this forum. Without reading through the dozens of pages ...
2
votes
1answer
142 views

Recommended High Voltage Supply Circuit

Are there any circuit template I could look into if I want to achieve the following specification stated below: Input: 5VDC Output: 1kV, 0.5mA I was looking into the flyback convertor but I am not ...
1
vote
1answer
170 views

Transformer for variable output off-line boost flyback converter

I've built a flyback regulator that can produce 100-400V from mains, but -- due to limited off-the-shelf transformer options -- I'm pretty sure I'm not using the best transformer for the job (unless I ...
3
votes
1answer
385 views

The flyback diode and its applications

So in an application like this: The coil of the motor will, by Lenz's Law, induce a very large negative voltage across its terminals (without the diode in place). Would this voltage be very ...
5
votes
4answers
1k views

Why is flyback air gap needed for energy storage?

Why do so many sources say something along the lines "since a flyback transformer stores energy, an air gap is needed"? I have seen this reasoning in textbooks and app notes. I thought air gaps ...
0
votes
1answer
217 views

Building a decent 12V power supply from batteries

I'm currently building a flyback transformer. As you can see, the power supply is 12-15V, 3A. Up until now I've been using a 12VDC power supply from batteries. I guess I should have realized sooner ...
0
votes
2answers
551 views

Flyback transformer construction issues

Previous thread: Flyback transformer So, in short, I'm attempting to build a flyback transformer. The schematic I am using is this: And the flyback core looks like this: Upon recommendation ...
1
vote
3answers
111 views

Can a reed switch be used instead of a flyback diode?

Just wondering, a flyback diode is typically used to protect the circuit. Could the magnetic field generated by the flyback be captured to drive a reed switch and protect the circuit the same way a ...
5
votes
3answers
603 views

Solenoids causing Arduino to malfunction despite protection diode

simulate this circuit – Schematic created using CircuitLab I have an Arduino Mega that I'm attempting to control some solenoids and LEDs with. The LEDs are 3.3V, controlled through an ...
0
votes
1answer
785 views

Flyback transformer

Recently, I posted a question about a flyback transformer schematic I was having. If you didn't check the link, I was having problems with the frequency of the 555 timer as well as problems with ...
0
votes
3answers
426 views

Need a protection diode if only connected by common ground?

I have many solenoids running on 25VDC. Some are controlled by MOSFETs which are powered by a 5VDC circuit, and others are controlled by physical switches in the 25V lines. The 5V and 25V circuits ...
2
votes
2answers
521 views

Flyback transformer - ambiguous schematics and other issues

I'm currently using schematic for a flyback transformer. As you can see, there's a big problem - neither the schematic, nor the website describing it, give the value of the capacitor. It says ".01", ...
0
votes
3answers
155 views

Transformer for Flyback power supply

I am designing an isolated DC-DC converter with an input of 12V and an output of 5V@12A, at the moment, a flyback seems like the best option. I have read several books regarding the subject and I am ...
0
votes
1answer
102 views

Is a flyback supposed to have infinite resistance on the secondary (arc) coil?

Previously, I was able to get nice arcs with the 555 timer and irfp450 MOSFETS. When they died out I thought it was just the FETS but when I went through the proper test procedure for the FETS, I ...
1
vote
2answers
989 views

Getting Right parts and building ZVS flyback correctly

I recently built a 555 timer flyback driver. I used 2 IRFP450 MOSFET's in parallel to drive it and I got pretty good arcs. Something always seemed to fail, and I always was buying another 555 chip or ...
2
votes
1answer
542 views

Why high voltage from TV flyback shocks you without the need to complete a circuit?

Assuming the TV is plugged into an isolation transformer (although I think there is already a small transformer onboard), then ground is not part of the secondary side. Yet, high voltage from flyback ...
4
votes
2answers
1k views

Do I need a flyback diode?

I have some experience using automotive relays and triggering them using the output from a two-way radio aux pin so I am aware of the need to add a diode in parallel with the coil to protect the ...
9
votes
2answers
2k views

Flyback diodes issues and pull-in & hold current issues in this Relay circuit

Although this may be a basic question but I'm still struggling with it. In this schematic, two zener diodes D1 and D2 are connected back-to back across relay coil L1. The BVds = -30V for Q1. Can I use ...
0
votes
0answers
712 views

Can SPICE simulate inductive device flyback effects?

Following up my earlier question, can SPICE simulate inductive device flyback effects? I would expect so, because this would seem to be a critical part of simulating a switching power supply design. ...