An transconductance (using voltage to control current) electronic component used for switching and amplification. Acronym for Metal-Oxide-Semiconductor Field-Effect Transistor. (from http://en.wikipedia.org/wiki/Transistor)

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33 views

How to use LM56 to switch on/off a 2kW heater using a MOSFET

I have an oil heater at 220V/2000W so lets say 10A (maybe more when it starts?!). I was thinking of creating a circuit to switch the oil heater on/off with a LM56. Is it possible using a MOSFET ...
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1answer
97 views

MOSFET Amplifier?

I'm trying to create an amplifier circuit using a n channel MOSFET and I can't seem to get the results I'm looking for. I'm trying to amplify an AC signal up to the +/- Vcc but I keep getting strange ...
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2answers
50 views

Optoisolation and Mosfet combo

I want to switch a Thermoelectric Peltier Cooler (TEC1-12705) (12V - 77 Watts) using an Uno. I am an engineer but not an EE so I could use some guidance on circuit setup. There was a very good ...
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38 views

Strange output waveform of the high-side load of MOSFET

everyone. I am using a MOSFET as a switch to drive a laser diode. I input a periodic signal to the Gate of the MOSFET and I obtained a strange high-side load waveform. Here is my schematic. When I ...
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2answers
166 views

Power switch with slow control signal

I am trying to switch on and off a circuit that draws about 0.8 amp at 12 V. The obvious choice is to set a MOSFET. The problem is that the control signal (the one that goes on the gate of the MOSFET) ...
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2answers
131 views

Make a zener diode out of a MOSFET

Does anyone know if its possible to wire up a MOSFET transistor as a zener diode? I have been happily making normal diodes from my MOSFETs by shorting the gate and the source simulate this ...
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2answers
44 views

Power Transistor Help

I'm looking to switch an 18v signal at 1 amp with a N-Channel power MOSFET with at least 1.5v to turn it on in a TO-220 package but unfortunately I've only been able to find this one from Fairchild: ...
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1answer
40 views

SCR triggering and ground loop issues

I am trying to trigger an scr/thyristor from a 0-5V TTL pulse (channel 1 on the oscilloscope output). The schematic can be viewed below. I am using the TTL to pull the 2n2222 transistor 'on' which ...
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3answers
123 views

Solid state circuit to charge caps in parallel then discharge in series?

Do there exist a solid state design circuit to do the following: Charge multiple capacitors in parallel for a certain amount of time from a low voltage DC source, then disconnect them completely from ...
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22 views

Sepic hardware 2 [duplicate]

Hi i am attaching more images, i hope you would understand img. 1 is the waveform at 8 V input is applied to the Sepic converter. img 2-4 are various low voltage (below 2V) applied
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1answer
34 views

Selecting MOSFETs for Motor

I want to implement a driver circuit for a (sensored) motor that I am purchasing which has the characteristics (on the shopping website): Max Amps: 16 Max Power: 350W ESC: 35A KV: 1900 The ...
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3answers
71 views

Hot MOSFET DC-DC Boost Converter

What: I'm designing a DC-DC Boost converter for a solar panel maxmimum-power-point-tracker (MPPT). Setup: I'm using a TPS2819 MOSFET driver connected to a FQD16N25C N-MOSFET. The TPS2819 is driven ...
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1answer
70 views

problem with LED Matrix circuit

I want to create a LED Matrix circuit with 74HC595 shift register and 2n7000 mosfet. The schematic is as follows. I have mentioned voltage levels at various points. All the control signals of ...
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1answer
289 views

Very hot mosfet when powering an led strip

I'm basically following this instructable which is using an arduino to control an rgb led strip. I have wired it up exactly as shown, although I didn't use a breadboard i just soldered everything. ...
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4answers
85 views

Zener + MOSFET overvoltage protection

I need a simple circuit to protect my device from overvoltage (more than 13V). Typical working DC input voltage is 7-12V. Can I use this circuit: Will it work? UPD. OK, it will not. I was too ...
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31 views

Designing an Automated Switching System for Solar Battery Charging Station

I am trying to design an Automated Switching System for my Solar Battery Charging Station project. In the project a 48V battery rail is charged with two 200W panels connected in series through a PWM ...
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1answer
61 views

2N7002 Continuous drain current?

I'm currently looking for some MOSFET's to do some RGB LED lighting with using PWM. I found the 2N7002 in SOT-23 packaging (datasheet). According to the datasheet the MOSFET can handle a continuous ...
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2answers
74 views

Why one transistor switches on first than other

In the circuit diagram given below we have two transistors. And in the article it is given that one transistor will turn on first. Why this transistor turns on first
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2answers
94 views

Why do most N Channel MOSFET Circuits have the Source Pin tied to ground? + Circuit Question

I've noticed, when looking around the internet, that almost every circuit showing the usage of a N-channel MOSFET has the load before the drain, and the source pin is tied to ground. From what I ...
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54 views

How to combine a 555 timer and an MC34063

So, I've been at a project for a couple of weeks now, far too long in my opinion. I'm coming down to the final push and my last obstacle is to connect two circuits together to make a Piezo transducer ...
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1answer
89 views

Drive a 4.8V servo signal line using 3.3V

I have a servo with an operating voltage of 4.8V. I want to drive the servo from a MCU running on 3.3V. I haven't tried it yet, but was wondering if I needed to drive the signal line to 4.8V using a ...
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2answers
55 views

MOSFET package with lower thermal resistance than D2PAK

As far as PCB surface mount MOSFET packages go, does D2PAK generally have the lowest thermal (junction to ambient) resistance? Are there other packages with lower \$R_{jc}\$? This question is based ...
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1answer
75 views

What is the meaning of biasing in electrical/electronics circuits? [duplicate]

What is the meaning of biasing in electrical/electronics circuits? What is the need for biasing in BJT/MOSFET? What will happen after biasing when we apply input signal(AC/DC)? Will biasing signal and ...
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3answers
322 views

Why are MOSFETs used for VLSI IC fabrication instead of JFETs?

Why are MOSFETs used for VLSI IC fabrication instead of JFETs? What are some reasons the use of JFETs is not common?
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48 views

Dual active bridge converter

I'm having issues calculating the power losses associated with the operation of a bidirectional isolated Dual Active Bridge DC/DC converter. The converter is controlled using Phase Shift Modulation ...
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0answers
88 views

Mosfet as a Switch

I have created 2 circuits using altium designer as shown below: After simulation here is what i have for the left circuit: Right circuit: Basically, as you can see in the first circuit i have 2 ...
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1answer
111 views

Severe ringing when high side MOSFET in half bridge circuit switches on

I have designed a PCB (intended as a prototyping building block) that has a IR2113 high and low side gate driver driving two IRF3205 (55V, 8mΩ, 110A) power MOSFETs in half-bridge configuration: ...
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2answers
43 views

simple motor driver wouldn't work

I am using ATMega164PA as the microcontroller running at 8MHz on 3V coin battery (current battery voltage 2.5V). I am trying to turn on tiny coin vibration motor rated 3V, 90mA using ZXMN10A07FTA ...
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1answer
59 views

Current Mirror Sense Amplifier

I am unable to understand the working of the below circuit and how it act as amplifier. Enable the SAEN signal i.e. turning it high. Let us assume that we get DL as 1 and DLB as 0. Actually it will ...
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1answer
110 views

Switched capacitors using MOSFETs in filter design

I'm designing a State Variable Filter design using switched capacitors to control cut-off and resonance. Simulating this using idealized switches yields excellent results. See attached schematic ...
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0answers
50 views

How to bias a MOSFET folded cascode transistor using a cascode current mirror?

In the given picture how the folded cascode present at the output is biased. The method used by the author is direct voltage source biasing, but I wish to use a cascode current mirror but facing a ...
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2answers
143 views

How to replace this NPN transistor with a MOSFET?

Here is the schematic of the circuit I'm trying to build (source) but I only have an IRF9530N Mosfet; I don't have any NPN transistors at hand. What would the schematic look like with a MOSFET ...
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1answer
116 views

Why signal deteriorate in half-duplex UART communication in long wire (6 meter)?

I am doing project on half-duplex UART communication between two AVR microcontrollers. I am using n-mosfet based push pull circuit in both transmitter and receiver side. 3.3 V signals transmission is ...
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2answers
97 views

MOSFET behavior with small load resistor

I'm trying to understand the behavior of a MOSFET I got at radioshack (Fairchild IRF510). I have the circuit set up in the way recommended by the datasheet: The specifications suggest that it ...
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3answers
136 views

Complementary H-Bridge Motor control

I have some concerns in a motor control board I designed. Sometimes the MOSFETs unexpectedly start to burn. I suspect one of the reasons is the thin track (0.2mm) I have in my flexible board (0.2mm), ...
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4answers
191 views

Electronic flasher with low load detection

The circuit above is an existing flasher without low load detection. I am trying to develop electronic 2-wheeler flasher with low load detection. While Googling, I got a circuit with relay in it, ...
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2answers
78 views

How to determine maximum PWM frequency for transistor (2SK2554)

How can I determine (estimate) maximum reasonable PWM frequency for 2SK2554 transistor? I found timings in datasheet: I could estimate frequency from this (and make sure that all these times are ...
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1answer
438 views

How To Blink LED's with MOSFET in response to Music?

trying to blink LED's by music. i've done this circuit no problem: Now wish to accomplish the same thing using an N-channel Mosfet. I tried this circuit, and got no blinks. Also no success with ...
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1answer
120 views

Building my own brushless 3-phase motor driver to use with an Arduino

For educational purposes I want to build from scratch a PCB that would allow me to control an hard disk motor I scavenged from the trash. To do so, I was thinking about using AO3400 and AO3401 (PNP ...
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0answers
44 views

How does mosfet allow current to flow at the Pinch off mode?

I understand the mosfet other than in the pinch off mode? If the Inversion layer pinches off, how does it still allow the current to flow? Look at the bottom two images.
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1answer
183 views

Peltier heat resistor temperature controller, schematic issue

I've been having a problem with the following schematic: What I need to do: Two temperature controllers in order to create a temperature gradient. The hot side is a a little above room temperature ...
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2answers
69 views

Multi-stage High Side MOSFET driver

I have a system that has at most 10 20V batteries and each battery can push out 10A. At each battery I have a SPST relay disconnecting each positive terminal in the ckt. The SPST is driven by a 5V ...
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3answers
72 views

MOSFET off state at certain voltage?

I'm new to electronics and today I've discovered MOSFET transistors. It lets the current flow between source and drain terminals, when the voltage, applied to gate terminal, reaches a certain level. ...
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1answer
50 views

small signal analysis solve

I have found this small signal analysis circuit in my exercise. simulate this circuit – Schematic created using CircuitLab I tried both \$\pi\$-model and T-model but can't go anywhere. ...
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2answers
99 views

MOSFET amplifier

I found the following problem in the Rashid book of microelectronic circuits. I am looking to solve it but I don't even know where to start. How can I solve everything? What results do you get so I ...
2
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2answers
111 views

Better way to drive higher voltages

In order to drive pass transistors (MOSFETs) located between two non-zero voltage points, one can use a resistor divider followed by a MOSFET as seen here where V2 is high enough to drive the top ...
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5answers
178 views

Emulating a switch with open drain outputs

I need to replace mechanical switches with some kind of digital switch. Specifically I want to sent control inputs to various arcade games that use standard JAMMA inputs, which are basically switches ...
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1answer
98 views

Supply voltage for MOSFET driver in high-voltage (110v) PWM regulator

I am designing PWM speed control for 110v DC motor. Since it is 110v, I am going to power it from bridge rectifier connected to mains, with MOSFET on low side for switching. For driving MOSFET I plan ...
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1answer
100 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
115 views

Pros/Cons of using a Power MOSFET vs. a standard MOSFET

I recently sought (and received much great help) help with a brake light project from this site. That project went well and I installed it a week ago. Everything seems to be working as intended thus ...