## Distribution of surface charges along the wire

Distribution of surface charges with a constant gradient is present along the length of the wire which produces a constant electric field along the entire length of the wire. This results in constant current in all the sections of the wire. I am aware of the constant distribution of the surface charges at equilibrium but … Read more

## Siglent SDS Oscciloscope VISA disconnection

I’m currently connecting my Siglent SDS1202X-E Digital Storage Oscilloscope to my lab PC using a USB cable. I took advantage of the VISA interface that it has and used PyVISA package to write script for automated testing. However, although the Python scripts worked fine, the scope kept disconnecting from the PC occasionally. Any help would … Read more

## How to run LTSpice from terminal in Linux?

I’ve installed LTspiceXVII on my linux machine and it is running fine, but I cannot get it to run a simulation using the terminal. This is a necessity for me since I want to automate a circuit via python. Here is what I’ve run: \$ cd ~/.wine/drive_c/Program Files/LTC/LTspiceXVII \$ wine ./XVIIx64.exe -Run -b examples/Educational/opamp.asc But … Read more

## What do the EE and BB fields look like around a length of pipe, excited from one end by a Class A amplifier?

Diagram here: I’m looking for help modeling the E and B fields around a length of pipe. One end of the pipe is connected to the collector of a transistor in a Class A amplifier. For simplicity’s sake, let’s say the pipe is 1 meter long. I know the voltage at the collector swings between … Read more

## Help understand the role of an inductor and its value (educated guess)

This circuit is a part of a field strength meter circuit in an old magazine, the value of inductor J1 is unknown (due to a print error in the magazine.) The circuit works like this: With S1 open and S2A connecting the TR1 base, we take signal from the A2 antenna and through the DG1 … Read more

## How to calculate total average power (in dBm) of a distorted voltage signal from power spectral density using scipy.signal.welch?

I am new to signal processing. I have time and voltage data of a signal that is a distorted sine wave and I want to calculate the total average power of the signal given a load of 50 Ohms. I do the following: import scipy.fftpack from scipy.interpolate import interp1d import scipy.signal R=50 datat= interp1d(data_t.iloc[:,0], data_t.iloc[:,1]) … Read more

## Use a waveform that is saved on a Siglent SDG1032X using Python Sockets

I’m trying to use a waveform that I already saved on my Siglent SDG1032X function generator. The Siglent is connected to a DSO-X 2004A oscilloscope that is used to visualize the waveform. I’m using Python Sockets to remotely control the function generator. I am able to connect to the Siglent and send commands. When I … Read more

## Helmholtz coil – I don’t understand the circuitry

I work in a testing laboratory. We recently introduced in our repertoire a testing method using Helmholtz coils to generate a magnetic field. In order to have a magnetic field I need to have current on that wire. In order to have current I need a closed circuit. What baffles me is the connection from … Read more

## Identify this 1980 vintage Canon calculator “all-in-one” IC

I am attempting to reverse-engineer a Canon “P10-D II” desktop calculator (assembled circa 1980). The main PCB is single-layer which makes life easier apart from the fact that I cannot find any information at all on the main IC. It’s a 40-pin DIP of 0.1″ pitch. The part number appears to be M58881P and there … Read more

## SPI communication problem between Raspberry Pi and STM32

I’ve spent a couple of days to find answer to my problem. Currently I’m working on a project where an STM32L432KC microcontroller board and a Raspberry Pi 3B need to communicate over SPI. The OS on the PI is Rasbian stretch, the microcontroller code is bare metal. The microcontroller’s code is the following: #include <stm32l432xx.h> … Read more