Top new questions this week:

Battery (Li-SOCl) voltage varying with orientation

We are using this 3.6V Lithium battery (ER14505) to power the micro controller circuit in one of our devices. The device is capable of reporting the battery level. Since the controllers brown-out …

batteries

asked by Rev1.0 13 votes answered by Rev1.0 11 votes

Is it possible to step-up the output of a laptop USB port to 12 watts?

I've got a USB device that requires 12 watts to charge. My laptop appears to output less that that. My question is: Is it possible to step-up the output of a laptop USB port to 12 watts?

usb watts

asked by hawkeye 10 votes answered by Olin Lathrop 24 votes

Understanding cause of arcing in AC filter circuit

I have an induction hot-plate that one day blew a fuse in my distribution panel when plugging it in. (With the obligatory smoke from the device of course...) On visual inspection, only the AC filter …

ac filter arc

asked by ARF 7 votes answered by Guill 0 votes

Outlets not grounded? Remedy?

For some months, I'm renting an apartment in the Canary Islands. It looks like the plugs are not grounded. For example, when I connect my laptop, a ThinkPad T420si, then I feel an unpleasant sensation …

transformer ground mains grounding outlet

asked by feklee 6 votes answered by Asmyldof 4 votes

Is it possible to create an IIR filter in an FPGA that's clocked at the sample frequency?

This question is about implementing a IIR filter in a FPGA with DSP slices, with very specific criteria. Lets say you're making a filter with no forward taps and only 1 reverse tap, with this …

fpga filter dsp iir

asked by Marcus10110 6 votes

How do I do basic circuit analysis with resistors rated in watts instead of ohms?

In my electrical circuits class, we've spent the last six weeks learning circuit analysis with resistors rated in ohms. Now, out of the blue, every question on the next practice exam has the resistors …

circuit-analysis

asked by BStott 5 votes answered by Brad 16 votes

Transformer current peaks

So I am designing a power supply, got everything calculated, and decided to simulate it for a second to see if the smoothing caps keep the voltage above the regulator limit at max current draw. What I …

current transformer transient

asked by Limiter 5 votes answered by Russell McMahon 8 votes

Greatest hits from previous weeks:

How to Calculate the time of Charging and Discharging of battery?

How do I calculate the approximated time for the Charging and Discharging of the battery? Is there any equation available for the purpose? If yes, then please provide me.

batteries charging discharge

asked by Farid-ur-Rahman 6 votes answered by Majenko 10 votes

What is it that strips vocals from audio when a 1/8" audio jack is partially unplugged?

Every once in a while, my eighth-inch audio jack will slip loose and I'll seemingly lose only the voice part of a track -- leaving somewhat of a "karaoke" version. What I would guess about how audio …

audio stereo

asked by editor 157 votes answered by Dave Tweed 290 votes

Can you answer these?

Why does my bandpass filter act as highpass?

I have designed a bandpass filter. Here is the circuit and spectral characteristic: As you can see from the response curve, it has cutoff with the peak ranging from 260 kHz to 290 kHz. Here is …

filter passive-networks

asked by Plutonium smuggler 1 vote

High resistance (100Mohm) control using constant voltage or current source

I want to control resistance (100Mohm) programmatically. I found on this site that photoFET can solve this issue by sourcing constant current. From my understanding FET can give resistance control …

resistance

asked by sai 1 vote

Is it OK to place ground plane under transformer?

I have a large transformer (50kHz, ferrite E-core) on the PCB. I want to pass power rails under it on the bottom layer. Should I place a large ground plane on the top layer to shield these power rails …

pcb-design transformer shielding ground-plane

asked by hkBattousai 1 vote