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1answer
32 views

Do I need to place any additional component(s) getween isolated grounds?

Initially I bothered with this question regarding isolated flyback switch mode power supplies. However I'd be happy to investigate this question dipper. So as the output of the power supply is ...
3
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3answers
235 views

Determine adequate speed of flyback diode for a relay

I have already looked at this question which looked like it would provide the answer: How to choose a flyback diode for a relay? But it didn't, so I also checked out these: ...
3
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2answers
81 views

Is a flyback diode necessary when no sensitive chips are used?

I have had a look through all the information available about flyback or snubber diodes in a relay system and was hoping to confirm if one is necessary in my circuit or not. All the info about why a ...
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3answers
121 views

Relay Spike at Vdd

I have a problem with voltage suppression at the time of relay switching. I use a transformerless ac to 12v dc conversion circuit similar to (I use 12V zener and 470uf capacitor) : ![enter image ...
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0answers
52 views

How can I add redundancy to the flyback diode protection across an inductive load?

Dear StackExchange users, I want to add redundancy to a flyback diode system that is protecting an N channel MOSFET from flyback of an inductive load but I don't know how to accomplish this! I am ...
0
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1answer
45 views

ESD protection on a solenoid driver circuit

I have a breadboard circuit that controls some solenoid valves and am trying to move it to a PCB along with improving it for ESD and EMI. This is the circuit I have on the breadboard that I want to ...
0
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1answer
54 views

How different is the performance of TVS vs Zener diode in flyback protection

So far I know that it is possible to protect a Switch, MOSFET, Relay from flyback with different kind of diodes: One diode: It is simple but it affects the speed of valve One diode + a resistor: ...
0
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1answer
115 views

How does flyback diode decrease the response time of a solenoid valve

Dear all StackExchange users, I want to make a circuit consisting of 8 valves. Each valve has 55mH and 33 ohm. I want to control them with an Arduino board and a proper MOSFET. Valves reaction time ...
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1answer
25 views

Does zxms6004ff come with flyback diode internally?

As question above, does anyone know better about product from DIODES? I am using zxms6004ff, but not sure about if it comes with flyback diode internally? I read over their datasheet. It only says it ...
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2answers
52 views

How to calculate discharge time of DC motor via flyback diode in H bridge

The setup is as follows: DC Motor: Brushed DC Motor PNP NPN standard H Bridge with 4 numbers of 1N4448 for flyback protection. Stall current of the Motor: 200 mA (Stalling is expected) Typical load ...
3
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2answers
55 views

Relay noise problem although flyback diode is used

I've this relay (5V) with 1N4148 as flyback diode across the relay's coil but there's still noise problem. When I switch on/off the relay, the PIC MCU will occasionally reset and false triggered the ...
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3answers
462 views

Can a Zener diode that protects a switch against inductance when the switch opens, affect turn on speed of the valve while you close it again?

As you probably know, in the applications that the turn off speed of the solenoid valves are crucial, the simple flyback diode is not effective. Some people put a resistor in series with the flyback ...
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1answer
61 views

Procedure for finding the right MOSFET, diode and resistor to make a solenoid valve open/close?

I need a right MOSFET to make a 8 valves open/close about 15 times per second! It needs to switch very fast. Anything that can slows the speed of the valves is not desirable. From what I see the ...
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3answers
55 views

best way to rectify 30kv flyback output?

i have made a flyback transformer for some HV experiments and am hoping to get around 35kv from it, which i want to use to charge a capacitor, so i will need to rectify the output... i think perhaps ...
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0answers
32 views

Using a ballast to power a flyback transformer

I know there are many ways to power a flyback transformer. For example you can build a driver using a 2N055 transistor, a 555 or a ZVS. However I discovered that you can also use a ballast, as seen ...
0
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1answer
52 views

Why do Flyback Transformers have C-I cores?

Usual transformer cores are either E-I or E-E. What's the reason for Flyback's being only C-I? Does it simply cut the cost?? I want to know if it would perform less if it were an E-I.
1
vote
1answer
116 views

Resistor instead of flyback diode

I was looking at the data sheet of a common 12v relay and noticed it mentioned using a resistor instead of a flyback diode for circuit protection. On the last page for 12V models it reads; When ...
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0answers
28 views

What are important parameters for a flyback diode? [duplicate]

I need a flyback diode for a 12V/50mA relay that is switched by a BSS138 MOSFET. Do I need one or more of the following: Schottky diode fast recovery diode high current diode or would a 1N4001 or ...
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2answers
212 views

Where to add Flyback diode?

I have made a relay controller module which switches a automotive relay when a ULN2003A sinks current on the separate main board. The module is in an always active state, but the requirements have ...
2
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1answer
100 views

Standard transformer for higher-voltage dual output flyback converter

Is it possible to modify this flyback converter to get the output voltage somewhere up in the range of +/- 26-60v (preferably 30v or more) without having to make my own transformer? I would also like ...
1
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1answer
101 views

Flyback transformer pin connections

I took a flyback transformer out of an old CRT television. This is how it looks like on the top: And this is how it looks like on the bottom: http://i.imgur.com/8QYwPhQ.png W1 is a thick red wire ...
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2answers
100 views

Is this the behavior of a broken mosfet?

I designed this circuit to switch on/off 8 solenoid valves for a programmable dancing fountain that I am building. The GPIO is coming from a Raspberry Pi. VCC is coming from a 12V deep cycle car ...
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0answers
59 views

Output Diode Snubber in Flyback Converter

I just completed making 48W flyback using TOP224. It is a fairly old Controller as well as its old design book. I looked at some of their modern ICs and design books and found out some significant ...
0
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1answer
69 views

Flyback Transformer Saturation in Secondary

I am trying to select a flyback transformer for a prototype I'm designing. Almost all flyback transformer data-sheets I've seen provide only the saturation current for the primary winding. The ...
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2answers
103 views

Trying to understand flyback diodes and general diode orientation

Let's start with this: I know the top image is of a flyback diode. I also get that its purpose is to protect the power supply from a voltage spike when the electromagnet releases. So I've gotten ...
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3answers
138 views

Is a flyback diode needed if there are only inductive components on the circuit (Ex. solenoids)

I'm using relays to drive a circuit of solenoids. Do I really need flyback diodes on the controlled circuit if there are only solenoids on it? The driving circuit is already protected by flybacks. ...
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1answer
67 views

Derive Parameters for Unknown Flyback Transformer

I am designing a 1.7 kV @ 6 mA flyback power supply. The issue I have is that it seems to be extremely difficult to find any type of high voltage flyback transformers for the design. I bought a cheap ...
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4answers
100 views

Connecting a galvanometer directly to a microcontroller's PWM output

Is it a good idea to connect a galvanometer (100 µA panel meter) directly to a PWM output of a microcontroller (or any other digital device for that matter)? I set PWM frequency to approximately 10 ...
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4answers
126 views

Alternative ways to catch an inductor's flyback current

This guy had a bit of problem installing the flyback diode to his relays due to physical obstruction. Now if that is really an issue will this be a good alternative way, for perfboards and ...
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2answers
241 views

H-Bridge flyback diode selection?

I am wanting to make a motor driver using a SN754410 Quadruple Half-H Driver IC. The SN754410 requires external flyback diodes. Here is an example circuit: My question is, how do I choose which ...
2
votes
1answer
96 views

Can varnish affect the performance of the air gap in an SMPS transformer?

In the past I have built several switched-mode supplies using off-the-shelf transformers just using the datasheet properties without having to worry too much about their construction, however I am ...
0
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1answer
122 views

SMPS Transformer - Secondary voltage rating

I am designing isolated flyback converter with input voltage range 40VDC-110VDC, 5V/6A output. I am struggling with finding appropriate transformer since each and every one I found have lower primary ...
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0answers
93 views

Flyback (?) diode on the Solid State Relay output

I am looking at the recommended wiring diagram of this SSR and I am wondering about the diode connected in parallel to the load. Flyback diodes for inductive loads make perfect sense to me, but in ...
0
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1answer
161 views

High Side PWM motor driving circuit

I have two theoretical question about my circuit (that I have tested with a breadboard and it works, but I want to understand better some design choices): 1) As far the flyback diode is concerned, I ...
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3answers
393 views

Protecting microcontroller from inductive loads

I'm working on a project where I will be controlling a variety of loads (relay, solenoid, motor) from an Arduino and I'd like to make sure I build in enough protection for the microcontroller and ...
0
votes
1answer
115 views

Will a flyback diode prevent an analog MCU input from being destroyed in this schematic?

Quick question: In this schematic, would D1 prevent high flyback voltages caused by the motor going into the voltage divider network and destroying pin A0 on the MCU? Pin A0 can only tolerate 5V max. ...
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0answers
149 views

PNP BJT as a 'switchable' flyback diode?

I have an automotive ignition coil which I'm using as an ignition source for a project I'm working on. During normal operation, the primary coil current will be interrupted periodically to induce ...
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0answers
191 views

PWM and flyback diode dependency

I have to choose components for a pcb motor driver, there is a dependency that I have to take into account between the PWM frequency and the speed of the flyback diode? If yes, what it is? Thanks
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2answers
348 views

Circuit Protection re: Relay Coil

Is the flyback diode adequate protection in for the microcontroller in the following circuit? simulate this circuit – Schematic created using CircuitLab Will my circuit experience over ...
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2answers
121 views

Low noise voltage regulation

I have a circuit which currently runs off of either a 12VDC wall wart adapter, or it falls back to a 9V battery if the wall wart adapter is not connected. My circuit currently uses a chip which ...
1
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1answer
93 views

Flyback converter current flow?

If you look at the flyback converter circuit above, the current only flows in one of the coils at any instant of time. What stops the magnetic field generated by the coil in series with the MOSFET ...
0
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1answer
73 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
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1answer
153 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
115 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
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1answer
98 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
111 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
161 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 ...
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2answers
264 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
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1answer
427 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: ...
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2answers
399 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 ...