71–80 of 169 posts
Keep your TIPS, you might not necessarily use them for that brand new design of yours, but you'll probably use them for something.
There is nothing wrong with bipolar transistors. They aren't antiquated. FETs have definitely overtaken them in power applications (for good reason) but it seems hard to displace them for small signal applications. Small signal FETs just aren't that plentiful or cheap. There are many instances where a small signal FET makes sense (level translators, etc) but the cost doesn't justify its use. Using a 2n2222 and the li…
The article seems mostly right when it's about interfacing logic circuits with loads that require even moderate currents. FET is king in this field. I've a little aquarium and I've noticed how fish always get scared when lights turn suddenly on or off. So I took an Arduino and wrote a timer app for it, using PWM to slowly drive the output up over 60 minutes (sunrise), keep it at max for a few hours, then drive it dow…
PT4115, pretty cheap on ebay and other usual places.
Earlier quoted context omitted.
>In particular, this made me sad: the 10K resistor to ground isn't strictly necessary, but it ensures that the MOSFET remains OFF if the arduino is disconnected or it's pin is not an OUTPUT. Not sure why that made you sad (extraneous ' in its?). But I agree about the static-sensitive disadvantage of MOSFETs. Also, the author mentions that a TIP120 is not a transistor but a darlington pair (two transistors in one) but…
It wasn't the grammar :-) it was that the author considered the 10K resistor to ground as "not strictly necessary". It is critical if the microprocessor pin can float (tri-state). Without it, and a floating gate, not only will the FET eventually turn on, it can be damaged by excess charge build up.
If you want to switch power, MOSFETs are the way to go today. Voltage drop is near zero. Digi-Key has over a thousand MOSFETs in TO-220 packages. Here's one of the cheapest with a low gate threshold.[1] Probably good enough for most Arduino on/off applications. MOSFETs do have some problems. They can draw large gate currents for the first few nanoseconds of turn-on, which can overload whatever is driving them. The ga…
I would love to see something on digikey or mouser that allowed me to search for MOSFETs in a way that was less painful. Let's say you wanted to do a special purpose switching power supply. Digikey doesn't have a column for gate capacitance (for the mosfet), or Q (for the inductor). All that manual work to read datasheets is terrible, especially if your design takes a little while to perfect and some of the component…
Earlier quoted context omitted.
If I ever made analog audio equipment professionally, I would add an entire series of switches and dials that weren't wired up to anything.
You could label them like "warmth", "aggressiveness", "heart", and have people go apeshit trying to figure out the best setting for their song.
I'm an electronics amateur, got a question here: I use a PN2222 [1] transistor to switch a 5V supply through an infrared LED from a microcontroller. It works, but should I be using something better/smaller/more cost effective/more appropriate for the circuit [2]? [1] https://blog.bschwind.com/2016/05/29/sending-infrared-comman... [2] https://blog.bschwind.com/2016/05/29/sending-infrared-comman... (the resistor in the…
If you are trying to optimize for whatever parameters, then maybe there are better parts. But for something simple and basic like that, its fine.
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If you properly drive a 2N3055 (so all the way to 'on' or all the way to 'off') you'd have to put a pretty good current through it to get it to get hot. The trick is to use the highest voltage you can get away with (most power for the least amount of current). .6V * quite a few amps before you overcome the housings capacity to get rid of the heat. You'll need to properly drive it though and not at too high a frequenc…
> before you overcome the housings capacity to get rid of the heat. The thing is, most of these larger BJT parts were designed to be used with heatsinks, not usually standalone. IMHO, there's nothing wrong with dropping some voltage and dumping some heat. Sure, it isn't efficient, but if you size everything properly, and your project can accommodate the heatsink - then where's the problem? Heck, a long time ago you c…
In a pinch: any piece of aluminum U profile will do, just drill a hole in it and use some heat conducting paste.
I'm an electronics amateur, got a question here: I use a PN2222 [1] transistor to switch a 5V supply through an infrared LED from a microcontroller. It works, but should I be using something better/smaller/more cost effective/more appropriate for the circuit [2]? [1] https://blog.bschwind.com/2016/05/29/sending-infrared-comman... [2] https://blog.bschwind.com/2016/05/29/sending-infrared-comman... (the resistor in the…
While we are on the topic of using more modern parts, if you are controlling a motor as shown in the example, why not use an H-Bridge chip ?
If you want to switch power, MOSFETs are the way to go today. Voltage drop is near zero. Digi-Key has over a thousand MOSFETs in TO-220 packages. Here's one of the cheapest with a low gate threshold.[1] Probably good enough for most Arduino on/off applications. MOSFETs do have some problems. They can draw large gate currents for the first few nanoseconds of turn-on, which can overload whatever is driving them. The ga…
I would love to see something on digikey or mouser that allowed me to search for MOSFETs in a way that was less painful. Let's say you wanted to do a special purpose switching power supply. Digikey doesn't have a column for gate capacitance (for the mosfet), or Q (for the inductor). All that manual work to read datasheets is terrible, especially if your design takes a little while to perfect and some of the component…