Posts by Olin Lathrop
The reason the transistor is dying is because you didn't put a flyback diode across the relay coil. Relay coils have significant inductance. This means the current can't change instantly without t...
First, let's redraw the circuit a little more clearly, with logical flow left to right. This also protects the answer from possible changes to the question. As you say, Q1 is a switch to control ...
Yes, some BOM optimization questions like you mentioned could be on topic. This would include the general techniques for optimizing BOM costs. Getting into specific prices and vendors would be off...
I'm trying to drive a relay according to a 5 V digital signal, using this circuit: It works for a while, but then the transistor fails. When I replace the transistor, it works for a while again, ...
One possibility is to use a transformer. The power input can then come from across the plus and minus input power. The output can be referenced to whatever you like, which in this case would be g...
I don't know what the book has in mind, but your first point is the main reason I would want to filter out the high frequencies with passive analog components. Low noise and low distortion are imp...
Note that open-circuiting an inductor "resets" the magnetic field instantly. The downside is that this also generates infinite voltage for that infinitely small time. Infinite voltage is obviousl...
At first glance, your design looks reasonable. I assume D1 and D2 are really supposed to be on opposite data lines, and them both being on the A line is a typo? One thing that sticks out to me is...
Is there a scientific way to estimate the resistance of a pogo pin? Ultimately there must be, but it generally requires knowing things you don't know. Worrying about the resistance of the barrel ...
When should a transformer core be potted? Whenever you need some of Mechanical ruggedness. High dielectric strength. Minimize vibrations (and therefore audible whine) from capacitive, inductive...
My first knee-jerk reaction was to use opto-isolators. There are some that have been around for decades and are unlikely to go obsolete any time soon. I wasn't previously aware of these "digital ...
What you basically ask for can be done (I've done it), but not all your specific constraints can be reasonably met. The way to measure transmission line impedance is to drive a step onto the trans...
Summary "Outdated" should be used for "this won't work anymore today", not "we would do this differently today". Detail "Outdated" should be reserved for when an answer is wrong or misleading be...
Can anyone explain the theory behind this pin You have already done so yourself: used to give a common mode stabilization and thereby reduce radiated emissions As far as I know, that is exactly ...
What is a typical value for capacitance of a real inductor? "Typical" capacitance is a useless to design circuits with. It will also vary considerably by inductor size, geometry, and materials us...
What the "appropriate" value of R1 is depends on what you are trying to achieve, which you haven't told us. Will this device be used in bright light, like outdoors, and the LED therefore needs to ...
That's a rather strange thermal relief pattern. It's also not clear where the hole is supposed to be. A proper thermal pattern has a plated hole and annular ring around the hole as usual. Then t...
I see you already have an answer based on the device physics. I'll answer that this means in a circuit. BJT (bipolar junction transistors) do work in reverse, at least somewhat. Generally, the c...
"Stream" and "memory mapped" should be defined in the documentation for whatever microcontroller you are using. "Memory mapped" can mean different things. It might be just a different way of sayi...
I think such questions are OK as long as they are EE-specific. General purpose dictionaries often do a poor job with specialized technical terms, especially when they are the same or similar as re...
We don't just give direct answers to homework (or homework-like) questions here, but can help you work thru the problem on your own. You might consider trying to synthesize a subtractor from scrat...
This is a good question. I wasn't originally envisioning introductions to known concepts, but that might work if well written. If so, the Paper should at least be clearly labeled as such. We don...
Sorry I didn't notice this earlier. We definitely don't just want to import questions and answers directly from SE. This has been discussed several times on various Codidact sites. Some of the f...
say that materials should be small and focused There are many many theories of how to best present information. Any one or two particular opinions aren't really relevant, especially since there i...
