Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [3.3v]

Deprecated tag. Do not use in the future.

Deprecated tag. Do not use in the future.

249 questions
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5 answers

What is a popular cheap and robust substitute for 2n7000 MOSFET for use with 3.3 Volt designs?

What are the popular equivalents to the 2n7000, for 3.3 Volt MCU circuits to switch higher voltage devices? Background: For 5 Volt microcontroller based prototypes and experiments, my go-to solution for low frequency, low side switching of 50-200 mA…
Anindo Ghosh
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4 answers

For 3.3V microprocessors, what's the best way to power the gate of a MOSFET?

The new processors are all 3.3V and dropping. So while I am used to 5V arduinos being able to power the gate of a MOSFET, at least most of the way, this is not going to be true any more. And for an IRF630, someone pointed out that I really need to…
Dov
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18
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3 answers

How do I use a 5V relay with a 3.3V arduino pro mini?

I'm using a couple arduino pro mini's (3.3V) for a home automation project and want to add relays to the final PCB design to switch some stuff on and off. Since I want to use a 5V relay like this: HF 46F 5V, Miniature HF power relay, 5 V, 1 NO 5 A I…
Blacky
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13
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1 answer

How is this circuit for level converting (5V<>3.3V) working?

Does anybody know, how is this circuit exactly working? It is level converter between 5V and 3.3V logic and it is bi-directional. I have some theory, but I am not sure with it (I never worked with MOSFET before). And what is that diode for? I take…
vasco
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11
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4 answers

Is it possible to drive TTL inputs from 3.3v microcontroller

I need a quick heads up on a problem I am trying to solve at work. I'm trying to connect to a parallel data port on an interface module we use to access smart cards. The port has an 8bit input and an 8 bit output with associated strobe/ready pins. I…
ttt
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8
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1 answer

which is better? 5V or 3.3V as the supply voltage

I am about to design a new microcontroller based project. I checked all components (few) and all can operate at 3.3V or 5V. the microcontroller itself can also operate at 3.3V or 5V (pic micro at only 4MHz oscillator). Well, the question is, what…
fhlb
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1 answer

MOSFET choice for 12v LED Strip and 3.3v Logic

I'm currently planning a project on a low-cost WiFi-enabled RGB LED controller and could use some help in looking over my parts list and general concept. What I'm wanting to do is a build a relatively low-cost, WiFi-enabled RGB LED (strip)…
Robin Heller
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3 answers

Bidirectional level swiching 5V <-> 3.3V

I am looking to interface a 3.3V device with a 5V one. This will require the shifting of the logic levels between the two devices. Doing this in one direction is a trivial matter, but I need to do it in both directions (reading and writing - it's a…
Majenko
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3 answers

MOSFET and 3 V power supply

I want to control an N-channel MOSFET from a 3 V power source. The thing is, I have difficulties understanding how to know the minimum Vgs value is to be applied for the MOSFET to be saturated. For example, what about the MOSFET CSD19501KCS (80 V…
Aleks
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2 answers

Converting universal AC to 3.3v DC @ 0.1A

There's a bunch of topics around this but i haven't found something that fits my requirements. I'd imagine this is a fairly common thing though so any pointers would be appreciated Basically i want to design a circuit that can use mains power…
Antti
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7
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1 answer

Open collectors & 74LVC245

I am trying to interface a PS/2 keyboard to a MSP430 for a toy. The PS/2 keyboard runs off 5V, but the MSP430 microcontroller runs off 3.3V. So I have a 74LVC245 level shifter to convert between the two. Now I have this, however, I have discovered…
David Given
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1 answer

Voltage Level Shifting

I know there are similar questions on the site, but I wanted to ask it from a somewhat different perspective. I've got a 5V device (Device A) that can operate at 3.3V. I've got a 3.3V device (Device B) that does not have 5V tolerant inputs. I want…
vicatcu
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Any clever way to provide 3.3V with good current output from a 9V battery?

I'm sorry for any English mistakes as I'm not used with using it when talking about technical stuff. I have been using some ESP8266 WiFi modules with Arduino Mega for a project. They work with 3.3V Vcc but require some good amount of current (it can…
Bruno
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2 answers

5V Tolerance of 3.3V OUTPUT pin

Let's assume the following scenario: uC (@3.3V VDD) drives an I/O pin HIGH 3.3V (just to be clear, it's not an open-drain pin, so the p-channel mosfet of the output pin is actually driving the pin to VDD level) Pin is also rated as a 5V tolerant…
Nitro
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4 answers

Options for getting 3.3v @ 220mA from small batteries

I have a system running at 3.3v requiring 70mA at most times and 220mA at peaks (roughly 20% of the time). I'd like to find a way to power this from coin cell batteries or other small portable source. Battery life needs to be about 1h but size…
Antti
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