Posts by Olin Lathrop
Unfortunately the frequency legend on your graphs are too small to see, so we don't know how the left and right graphs relate to each other. However, what is certainly going on in the left graph i...
It's really not clear what exactly happened in that video. We see someone slinging a hook over the power line, then we see a white picture. We don't know what the cable was made of and where the ...
At first this sounded like it might be a classic case of forgetting the flyback catch diode across the relay coil. However, now that you've posted a schematic we can see that a diode is built into...
It seems you want to protect a device against power spikes. The power supply is nominally 12 V, but can have spikes up to 79 V with an impedance of 500 mΩ. Two timing values were given, but they ...
In addition to what Andy said, the DC servo method doesn't add impedance to the signal. Note that in your bottom circuit, the signal with the DC offset removed has an impedance of 1 MΩ at DC. In ...
Impedance Yes, impedance is "extended" resistance. Impedance is really a complex value, with resistance it's real part. The imaginary part represents pure inductance or capacitance (with opposit...
It's a balance. On one had, we want to be a store of knowledge. It doesn't matter what prompted a particular piece of information to be posted if it serves the long term purpose. We also don't w...
At 1 MHz it's probably not transmission line effects. It's not clear from your question whether the SPI bus works on the main board with the expansion board connected, but not when it's not connec...
Your proposed circuit will work, but "before the voltage drops significantly" is rather wishy-washy. I would at least use a second meter to measure the current. What you really want to know is th...
First clarify where this leakage current will be flowing. You seem to think that some parts of the solar panel will generate a small current thru the rebar into the ground, but where is the closed...
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...
No, I have not seen this circuit before, and don't know what source you may have gotten it from. However, I'm not sure that really matters. I don't know what exactly you are trying to teach, but m...
No, a resistor divider is not appropriate, at least not if you want to get all the information from the STAT pin. In addition, that chart in the datasheet is incomplete at best, or downright misle...
Since your noise has "unknown characteristics", you should do low pass filtering in analog before the discrete sampling of the A/D. The two parameters that matter are the frequency content of the ...
I was hiking around the Berkshires in western Massachusetts yesterday, and came across this metal panel where some power lines were crossing a ridge: The panel is a few meters wide, and appe...
Lower ESR can sometimes be a reason, as you say. However, most of the time the advantage is a wider frequency range over which the combined capacitor has low impedance or low dissipation. The fre...
PCB antennas are not designed by electrical engineers, but guys with pointy hats and wands They use trial and error after starting with the result of some mystic ritual including lots of mumbling ...
Sometimes cables between utility poles make a loop and do a U-turn. What is the purpose of such loops? The loop I'm asking about is in the lower set of wires towards the left of the picture. The...
This sounds like it could be a Paper (https://electrical.codidact.com/categories/35) if written up nicely. It doesn't make sense as a question because you're telling, not asking. I haven't heard ...
Repair questions can be on topic if it's about the underlying electronic principles. Just "How do I fix this?" is off topic. There is little wiggle room for trying to repair a consumer device tha...
Apparently you want to measure the current/voltage relationship of a tunnel diode. The tricky part is that the voltage isn't unique for currents over parts of the range. From your question: No...
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...
Yes, this is safe, but you do have to consider the layout carefully. You have to make sure that nothing conductive gets between the pads of each resistor. For this high voltage safety purpose, you...
