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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64 views

RGB LED strip, powered by an ATX PSU and controlled by PWM, makes my speakers buzz with Arduino connected by USB

I've not much idea about electronics, but I managed to do some little projects in the past. Now I'd like to place some RGB LEDs in my desktop PC windowed case. For that, I bought a 5050 SMD strip with ...
4
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3answers
107 views

Can I use a N-MOSFET to switch lower voltage signals?

I'd like to have a 12V signal as an input to a microcontroller, but it can only handle 5V on the input pins. This circuit will be used in a truck, so the "12V" signal can vary by quite a lot. My ...
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1answer
103 views

Specification Clarification for FETs

I use a MOSFET in my project, and I don't know what model of MOSFET I need. I do have a list of specs, but I don't know what they would be called on the datasheet. I need some help translating my ...
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2answers
36 views

PMOS, NMOS length width concept for low power circuit

Why for low power consumption width of NMOS taken same as length of feature and Width of PMOS taken as 2.5 times width of NMOS ? e.g for feature size 180n width of NMOS 180n and width of PMOS 450n. Is ...
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1answer
62 views

Which kinds of FET have a body diode

I need to detect small high and low peaks in the battery voltage while in use. The goal is to help estimating the end of the battery charge by its change in impedance, since my circuit uses the ...
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1answer
54 views

MOSFET controlled DC motor too slow

I want to control a DC motor using a P-channel MOSFET. I tried the motor with a 5VDC power supply. It works perfectly and speeds up in no time. I measured the current flowing through, it's around ...
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3answers
80 views

Circuit to switch about 5W of 12V using CMOS logic inputs using N-channel MOSFET?

I want to switch some 12V landscape light LEDs, totaling about 5 watts, using MOSFETs. I thought I had some logic level N-Channel MOSFETs lying around, but apparently not. What I have is several ...
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1answer
52 views

MCU Output Driver Verification

I am creating a circuit in which a MCU (STM32) must drive 12VDC outputs, and wanted to make sure there wasn't anything missing in my driver circuit for the outputs. ...
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1answer
27 views

Custom device with multiple gates tied together in Eagle

I'm trying to create a transistor array device in a small library I'm working on in Eagle. The device has five P-Channel MOSFETs. The source of each MOSFET is internally tied together and connected to ...
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1answer
68 views

Is a DVD sensor a photodiode or an array of them?

Is a DVD sensor just a photodiode or an array of them? I need to know if it is a CMOS with an array of them or just a single sensor.
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2answers
270 views

Why is there so much overshoot in my LED circuit and how do I prevent it?

I'm trying to PWM a 5 meter RGB LED strip with a microcontroller. With this setup: simulate this circuit – Schematic created using CircuitLab I have built it on a breadboard and probed ...
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1answer
128 views

Linear Regulator: MOSFET vs BJT

Currently I am doing a project on a voltage regulator. Can you tell me some advantages of MOSFETs over BJT? Apart from a higher power loss, I can not find much. In control engineering it is much more ...
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0answers
48 views

Driving LED from two supplies

In my design, I want to drive a LED using two different supplies depending on the control signal for n-mosfet. One of the supply will be disabled at boot-up. P MOS will be used to enable supply for ...
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1answer
115 views

MOSFET resistance

I'm trying to understand how MOSFET resistances work, but I'm seeing a lot of things that don't always fit together (probably due to my lack of understanding). Specifically the amplifier ...
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2answers
68 views

Can a high voltage difference force a MOSFET open?

I'm going to assume the obvious answer is no, but I figure I should check with the experts before I go off and waste a bunch of my time. Say you have several MOSFETS in a row controlling the flow ...
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1answer
73 views

driving a control pin to ground with different voltages

I'm using a 3.3V atmega2560 to disable a switching regulator that's operating on a ~12V battery. The EN pin on the switcher is pulled up to the battery voltage, and needs to be driven to ground to ...
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2answers
239 views

Does a logic-level P-MOSFET need a gate resistor?

I'm quintuple checking something I'm about to order from a PCB house, so bear with me. I'm using a P-channel MOSFET to power on/off a GPS chip. The chip's grounding is complicated, so I prefer to ...
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1answer
124 views

Why have my MOSFET drivers blown in this H-Bridge?

I've built a discrete H-Bridge circuit to run a reasonably beefy 12V windscreen wiper motor. The circuit is below (EDIT: see here for a bigger PDF, StackExchange doesn't seem to let you expand the ...
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1answer
52 views

Heating coil over-drawing current

I am currently designing a circuit that includes a nichrome coil used as a heating element. The wall adapter is 25V 5A DC, which leads to different buck converters that takes it down to the ...
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1answer
58 views

Inform microcontroller that the analogue circuit is powered up

Basically, I want to pull-down the microcontroller pin if some analogue circuit is powered up. The analogue circuit power is 9V, 1.6A. The idea I have is to use something like IRLZ24N MOSFET, connect ...
0
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1answer
85 views

n-channel MOSFET source load alternative

I'm trying to drive some RBG leds using MOSFETS. Let's say I have 2 individually RBG LEDS, each controlled by 12V, with each R, B and G with its own output to GND. What I want to control, is to be ...
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1answer
29 views

overdrive voltage margin to enter MOS into subthreshold and saturation region

What is the equation for Vgs value for any MOSFET in such a way that, Below Vgs, Mos is in subthreshold region, Above Vgs, Mos is in saturation region?
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0answers
85 views

2n3055 replacement with MOSFETs

I have searched a simple circuit diagram for a 12v to 220v voltage inverter. The circuit has two 2n3055 transistors and I presume it is used for switching. Can I replace them with IRFP250 MOSFETs ...
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56 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
113 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
64 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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0answers
50 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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1answer
46 views

Unexpected results in Multisim

I am in the process of selecting a N channel MOSFET for switching purposes and thus, tried out this simple circuit in Multisim. But it seems that the MOSFET conducts in the cut off mode and remains ...
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2answers
176 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
147 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
63 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
45 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
142 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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0answers
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
38 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
97 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
74 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
317 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. ...
0
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4answers
135 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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0answers
54 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 ...
0
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1answer
67 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
79 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
119 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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0answers
69 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 ...
2
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1answer
110 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 ...
4
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2answers
67 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
89 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 ...
4
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3answers
357 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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83 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
96 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 ...