0
votes
2answers
60 views

Why I can't get a clean signal from my opto-isolator?

I am trying to get working my first Mosfet H bridge. My H bridge characteristics are: 12v power supply 3.5A max current I need to control the bridge from a microcontroller 5V output About 30KHz PWM ...
1
vote
3answers
102 views

How do I drive a MOSFET working under high voltage while keeping it insulated from the rest of the circuit?

I want to drive a MOSFET with a 50Hz, 50% duty cycle clock pulse. The voltage to be switched is as high as 300V DC. The section inside the dashed lines will stay electrically isolated from the rest ...
0
votes
2answers
106 views

Debugging a garage door opener circuit with an optocoupler and mosfet

There seem to be many related questions, but I can't quite find the answer I'm looking for. I've got a garage door opener switch. There's 16V across the wires, and when you short them, the garage ...
4
votes
2answers
246 views

MOSFET controlled by optocoupler using Arduino

I have a question about using an Arduino to control a MOSFET with optocoupler. The question is, the supply voltage may vary from 5 to 36 Volts. For example, sometimes I will use a 5V switching ...
1
vote
0answers
295 views

Can You Drive Back-To-Back MOSFETs (aka a Solid State Relay) Without Using An Optocoupler?

I was wondering if there was any way of driving back-to-back MOSFETs (with their sources and gates tied together as shown in the following image) without using an optocoupler? The reason is that ...
7
votes
1answer
600 views

How is this 5-24V input circuit working?

Since I require some kind of wide range input (going to a microcontroller) for a new project, I looked through some designs that are already in use (or were considered at some point) for other ...
6
votes
1answer
4k views

Criteria behind selecting pwm frequency for speed control of a dc motor?

I'm working on a speed control circuit for a brushed dc motor (24v, 500rpm, 2A, 4kgcm). The main components that I plan to use are PIC16f873, 4n25 optocoupler, IRFZ44N MOSFET, BY 500 - 800 diode(for ...
4
votes
2answers
527 views

How to switch between a solar panel and battery?

A 12v battery is being charged from a solar panel. When battery is 12v solar panel is disconnected from battery and connect the load with battery. And again solar panel is connected with battery when ...
2
votes
2answers
480 views

Isolated MOSFET output stage calculations

I am a newcomer in this wonderful world of electronics trying to design my own PLC. So far I have designed a single output stage that I think will work, but it would be great if i could have any of ...
4
votes
1answer
1k views

Power MOSFETs and Gate drivers

I'm trying to finally apply what I learned at university in the course of power electronics. However I find that both that course and most of the books / online references are lacking on some points. ...
8
votes
3answers
16k views

How to drive a MOSFET with an optocoupler?

What's the proper schematic for driving this MOSFET from a microcontroller pin through this or this optocoupler? The MOSFET will drive a motor @ 24V, 6A.