robotmaker
I design alot of circuils been electronic engineer and was look at are using using switching transistors to turn on lights ,relays and more
Transistors are mostly old school design ,before mosfets came out,if you look at the h-bridges now that use mostfets instead of transisors
For a few reasons one is low RDS on ,with meens they can handle higher wattage and not get hot using transistors ,plus less voltage
The most common is n-channel and have 3 pins ,GATE witch goes to digital output with a current drive resistor then SOURCE witch is the load and DRAIN is ground
Now for protection for mosfets most have a diode that protect it from EMF or inductive kickback
MOST i see use diode on transistors from collector to emitter ,NOT a good idea manly it does suppress or stop the inductive kickback and if using a microprocessor or circuits with will get resets and more induce in th system
so where the diode goes is always across the coil with cathode (black line ) to postive and NO inductive kickback
DIODES are only needed for inductive loads ,motors and relays or coils
Not for resistance loads ,lights or heaters ,leds will put up a simple circuit
second part will be how to control AC products,RELAYS are also not good slow switching and as noises on the contacts that does resets but wull give info on how to fix them
HOPE this is easy to understand if not just ask a question
@Troy, I totally agree, don't get me wrong. I was pointing out that the circuit is already covered with clear to follow instructions. Any technical information that can be provided to aid someone in choosing the right thing for their specific situation is another matter but detailing building a circuit the same as one that's already detailed seems redundant to me, that was my point.
@Fred, I've not said you are wrong, please stop thinking that whatever I say is saying you are wrong. I don't dispute anything you have said in this subject and there is no need to become defensive. Yes the Mosfet was added after you flagged it up, there is a post from me explaining that if you flag something up I'll update the post (I can't remember which topic, you seem to cross over and spread over all topics), no intention of steeling your spotlight is intended as explained, it's all for clear and easy to follow instructions.
RICH where did i say you are wrong. So far what i see in every post i did on anything i am mostly wrong and never right on anything,and i went to school to learn and passed and got a degree.
I think i was right on only one post.yet like mosfets is my main field i work with and others
ALSO TROY if you noticed like on his project hearoid i only said good things about his project and gave him some real good ideas.
BUT not once has he said any of my project where good or any ideas.
TROY leave me your address,since i may get others email me when i dont want them too
Read slower, understand, post if you need to. You obviously haven't read it correctly.
And if by others you don't want to have your email address you mean me don't worry, I have your Jamericanfreddy email address...
As for mosfets, the IRLZ34 is a really good choice. It's logic level so it'll work with the EZ-B and other microcontrollers, it can drive 30A at 55V and it's nice and fast. I'm currently using it to PWM dim a 3W RGB LED.
I like Mosfets. Their tough little suckers. US pinball manufacturers started using them in some of their circuits back in the 1980's because they were more reliable.However the humble switching transistor never went out of style. The only drawback I know of with them is that there is no way to test them to see if one is shorted out or open.
Ferd, what institutions did you attend and where did you earn your degree? Hope not to offend with this personal question.
first who is FERD second is U OF M COLLEGE,was going to get my masters at FIU but at that time it was too hard with work and then going to school.
I know my grammar is bad only because i havent used it in so many many years or needed it,but as you can see its much much better.
Mosfets are made from darlington transistors and its a better upgrade,one main reason it was made.
Where on darlington transistors it has very high resistance and mosfets super low ohms ,but easy to use and some are logic level ,with meeds direct connection to cpu or logic
BEST example is H-BRIDGE is you look at the long time ago when they came out they use transistors to make them ,and now they use mosfets ,so ask your self the question why did they change to mosfets ?
NEIK yes IRLZ44 is a very good choice its called a logic fet,i have some of those.
One i am using is in a smaller package 17 amps high wattage and lower cost $.77 plus no diode is needed its has one built-in
Main reason i picked this one is small size and high current without a need for a heatsink,but mostly using mosfets or transistors a heatsink is not needed on some designs.
PLUS like most guys here everyone wants to save money ,so very low cost over a transistor.
Nothing wrong with using a Transistor as a switching device.
Here is a little background on when transistors and mosfets first came out
TRANSISTORS came out in 1948 and about 10 years latter mosfets came out in 1959 s a improved replacement.
Info is on the WIKI site on both of them.