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15
votes
2answers
722 views

Increasing the compliance voltage range for a variable, two-quadrant constant current pin-driver circuit

The following is for hobbyist work and I have no commercial intentions at all. Only a handful (two?) will be built. (I use these for part testing and curve generation, though with the higher voltage ...
12
votes
2answers
3k views

DRC tool for Gerber files

Do you know any tools which perform design rule checking for Gerber files of PCB and are suitable for using in batch mode on a remote server? Something similar to what BatchPCB or FreeDFM uses (I ...
11
votes
0answers
337 views

Switch from JTAG to SWD with bitbang sequence on STM32F103VB

I am trying to switch from JTAG to SWD without any external devices. Why? Because I would like to use the SWO pin to send a stream of logging information to another device. To accomplish this ...
9
votes
3answers
331 views

Digital Signal Cables Penetrating a RF Shielded Room

Disclaimer: I'm not a trained electrical engineer...I'm a recent Computer Science grad with about ten years experience as a RF test tech. I don't know everything, and to me, experience reigns supreme ...
8
votes
2answers
170 views

Which part of some LED TV screens acts as two gratings crossed at non-straight angle?

Some modern LED TVs display the following diffraction pattern (photos taken from this question): In my answer to another question about the origin of this pattern I explained that this should be due ...
7
votes
1answer
4k views

STM32F407 + LAN8720A + lwIP + FreeRTOS = No received Ethernet frames

I'm trying to bring up a PCB that uses an STM32F407 and LAN8720A Ethernet PHY, and I can't seem to receive any Ethernet frames — even though I have no problem transmitting frames. Hardware setup I ...
7
votes
1answer
4k views

Stability factors of a voltage divider bias circuit

I am trying to derive the stability factors of a voltage divider bias circuit. I could derive S,S', however, I'm facing some problem with the derivation of S''. Please help me in this regard. How to ...
7
votes
2answers
133 views

Compute spatial integral using analog computing

Let me start by saying that I am not an electrical engineer but a mathematician, who just started to dive into the world of analog computing using for the moment Simulink to simulate an analog ...
6
votes
1answer
90 views

Voltage Controlled Current Source - help needed

I am designing a voltage controlled current generator for the currents in a range from 0 - 2.5mA. The load resistance is within the range of 0 - 5k Ohms. I decided to go with difference amplifier ...
6
votes
1answer
286 views

Design of cavity filter

I try to design a Chebyshev bandpass filter for 6 GHz as a coaxial cavity filter. I know that the filter can be designed with the aid of the coupling coefficients between the resonators and the loaded ...
6
votes
0answers
497 views

LM386 guitar practice amp circuit not working, need help finding mistake

I'm very new to electronics and I built this guitar amp circuit on a breadboard: and it was working really nicely. Now I've decided to put the circuit on a universal PCB which I'll use in the actual ...
6
votes
1answer
433 views

GPS Power consumption MTK3339 vs SirfIII for periodic logging application

I am currently working on redesigning a SirfIII based battery operated GPS logger. A MTK3339 based GPS module has been selected due to overall (advertised) performance. The GPS logger uses a ...
6
votes
1answer
243 views

ARD00280 Microchip Energy Reference Schematic Live and Neutral Swapped?

Looking at the Microchip Energy Chip reference design I noticed that the power is being sampled from neutral. My first reaction to this was this is backwards, that the power should be sampled from ...
5
votes
0answers
65 views

“Temporary boost” supercap

I have a 12VDC load (up to 10A) that functions correctly down to 8VDC. Sometimes (frequency: many seconds max, many minutes typical) the power source has a very brief (few milliseconds) drop to 7V. ...
5
votes
3answers
125 views

Removing output voltage ripple in high voltage outputs

I am looking to reduce the voltage ripple on a DC/DC converter operating at 5kV. I have looked extensively on the internet and have found multiple ways to reduce output voltage ripple, an ...
5
votes
0answers
178 views

Is JTAG faster than SWD for debugging on an STM32F with STLINK-V3SET programmer?

There is a new STLINK-V3SET programmer that someone dropped off on my desk today. It supports USB 2.0. My thinking is that if SWD is the bandwidth limiter in the signal chain then a new programmer isn'...
5
votes
1answer
97 views

Can somebody please explain to me the principle of a T-T Earthing system?

How are the transformer, consumer's side and the generator earthed in a T-T Earthing system? I seem to understand that the generator and its frame should be earthed separately; The neutral of the ...
5
votes
2answers
269 views

How to calculate the impedance of a rectifier?

I am working on RF energy harvesting. Now I am trying to calculate the impedance of the rectifier, in order to do the impedance matching. An antenna (50 ohm) receives RF signal (915 MHz) and finally ...
5
votes
1answer
95 views

Altium testpoints auto-placement

Is there a way to use Altium to automatically generate test points on an already routed board? When there is no usable via, I'd like to place a pad on the net. When reviewing Altium API reference ...
5
votes
2answers
273 views

Ultra Low Consumption White LED Flasher

simulate this circuit – Schematic created using CircuitLab I need an LED flasher circuit to operate inside small model lighthouses. Ideally the flash needs to be white and the battery needs to ...
5
votes
1answer
307 views

High-Level Synthesis (HLS) vs RTL for ASIC flow

I'd like to know when it's a good idea to use HLS over RTL (Verilog/VHDL) design if I'm targetting ASIC implementation? Can synthesis tools like Design Compiler convert HLS C/C++ into gate-level ...
5
votes
1answer
951 views

How can I simulate an NTC on LTspice?

I have a schematic for a temperature controlled device which should operate at a particular temperature. For that I am using an NTC, now I have done the math by hand but it is more efficient and ...
5
votes
0answers
121 views

Contact a very small area (impedance matched)

In my current project, I want to apply a voltage to a capacitor (top electrode on a thin film heterostructure) very rapidly. Since capacitors have their own charging rate \$(\tau = R \cdot t = R \cdot ...
5
votes
2answers
163 views

Current Regulation Drift

Over a 200ms period of which this circuit regulates a 500mA current, the current drift downwards for about 0.4%. At first I thought it was due to R202 temperature coefficient, but from my calculation ...
5
votes
0answers
277 views

Mazzilli flyback driver mosfets keep failing

I've been trying to build a high voltage generator consisting of a high-voltage transformer and a Cockroft-Walton multiplier. I have actually tried several different drivers to drive a high-voltage ...
5
votes
3answers
264 views

Analog Computer Wiring

I'm trying to implement the following schematic of a simple analog computer The inputs are x and y, according to the text where I found this diagram the circles represent voltage dividers or ...
5
votes
1answer
197 views

Induced power supply noise on switch contact

I have a circuit that has a 24V section and a 5V section, separated by opto-isolators and an isolated DCDC converter. Both sides of the DC-DC have decoupling caps, and the MCU has one per Vcc pin. ...
5
votes
2answers
202 views

How to write or generate test cases(or vectors) for automated production testing of embedded electronics?

My question is following: Assuming I have developed some embedded controller(board) which has some tens of digital inputs and outputs. It has embedded firmware, which performs some logical functions. ...
5
votes
1answer
636 views

Interfacing FPGA to an external chip and timing constraints

I have designed a system using Artix-7 FPGA on a custom board. The goal is to transfer 32-bit data to an external onboard chip whose data bus is an inout port. ...
5
votes
0answers
148 views

Incrementing net name for group in Eagle

I want to make 50 copies of the block below, but I need incrementing numbers on each of the net labels (these will go to a connector). I do not want each block connected to the other blocks. It would ...
5
votes
2answers
2k views

Odroid XU4 and Olimex MOD-IO by I2C via level converter

Long version Like some of you, I do electronics as a hobby and I'm relatively now to this, so I have a few questions regarding the communication between my Odroid XU4 and a nice I2C module from ...
5
votes
2answers
965 views

Designing/Predicting Output from Permanent Magnet Motorcycle Stators

I'm hoping you can help me. I've long been into motorcycles, and have restored and customized many different bikes. While building custom motorcycles, I often add electrical accessories, and use high ...
5
votes
2answers
185 views

Which is the preferred approach to PCB layout for signal vs power traces in analog circuits, and things to consider?

I have had to layout 2 layer PCBs several times now for analog signals, and am just beginning to learn the process. I often face a similar question in one form or another with regard to laying out ...
4
votes
0answers
132 views

Why does the IC not respond (INA200)

The questions I have: Is the makeshift IC I use in the simulation a fair representation of the INA200? I assembled the circuit as shown in the picture (except for the current source and the LED) and ...
4
votes
2answers
102 views

What is the value of this 5-band resistor

The colors are black, light green, green, red and silver (looks more like gray). I am not sure which side to start reading the values from. Both ends seem to be symmetrical. Moreover, I have never ...
4
votes
3answers
132 views

How can I realize this nonlinear resistor?

I want to know if it's possible to realize a circuit described by the equation $$I = \sin(w V)$$ where \$I\$ is the current, \$V\$ the potential and \$w\$ a variable which characterizes the single ...
4
votes
1answer
112 views

Wireless Power Transfer for a toothbrush

The general idea is to charge a cordless toothbrush from 12V DC, instead of the mains. I have used a simple circuit that I more or less lifted from a Linear AppNote/Demo manual (DC1969). I would like ...
4
votes
0answers
65 views

Photon count with ADC, am I doing it right?

I have this LED and I want to characterize this photodiode. The LED should produce light of 370 nm, but I measured it and it is around 358 nm, and at that wavelength the quantum efficiency (\$\eta\$) ...
4
votes
1answer
189 views

Is this a reasonable, robust way for detecting voltage crossing a threshold?

Updated, functional design at the bottom of this question I wish to detect when a low-impedance signal is below or above 60VDC (±3V). When the signal is above 60V, I'd like to indicate this by ...
4
votes
0answers
59 views

What is the relation between resonance frequency and piezoelectric charge coefficient?

We know that the maximum power is lost at the resonant frequency,where the impedance is minimal. On the other hand, when the impedance is minimized, the charge coefficient is maximized. In resonance ...
4
votes
0answers
82 views

Radio module resetting when fluorescent tube switched on/off

I have a PCB powered by an IRM-30-12 power supply (230VAC to 12VDC). On this PCB, I have a MRF24J40MD from Microchip and a Udooneo to drive it + a 5VDC regulator and the 3.3VDC of the Udooneo. After ...
4
votes
0answers
106 views

VHDL Procedure - Same variable for input/output parameter

I've written a component where I use the same variable for the input and output parameter of a procedure. A reduced example looks like this: ...
4
votes
0answers
95 views

Subthreshold Analog Accelerator - How is current derived through two sub-threshold transistors in series?

Was browsing the following paper: Fick, Laura, et al. "Analog in-memory subthreshold deep neural network accelerator." 2017 IEEE Custom Integrated Circuits Conference (CICC). IEEE, 2017. When I ran ...
4
votes
3answers
152 views

What determines the frequency of network cable

You have Cat6, 23 AWG, rated for 250Mhz frequency. You then have Cat6a, 23 AWG, rated for 500Mhz. Both are unshielded. How is Cat6a able to transmit data at a higher frequency then its counter part? ...
4
votes
1answer
208 views

What antenna is this?

I just disassembled an external FM antenna designed for an old Asus laptop. I expected to find some circuitry and a monopole or some other simple antenna. However, what I found was the antenna shown ...
4
votes
1answer
174 views

Is probe compensation of a scope only for 10X setting?

I can understand that the idea of probe compensation is to make the sensed signal to be frequency independent as shown below 9C * R = R * 9C: Does that mean that probe compensation should be done ...
4
votes
1answer
216 views

How to cure SMPS output to get upset by a switching device

I have been having ringing spike issues at the output of SMPS power supplies. I don't know what is this phenomenon is about but it is definitely related to switching devices on the same electrical ...
4
votes
1answer
302 views

Undefined signal in simulation

I am trying to verify a design written in VHDL using SystemVerilog's assertions. however I got a problem when I have a non defined signal'X' Just for example here is a code of a Comparator: ...
4
votes
1answer
320 views

Safety Capacitor Selection

When selecting an X2 safety capacitor what must be taken into consideration. There are only a few types of capacitance ranges and seem to be chosen based on voltage rather than capacitance. Take ...
4
votes
1answer
342 views

Adjustable High current source (40A?)

I a looking for a schematic of a circuit to built an adjustable current source capable of delivering up to 40A. I am building a battery with 18650 cells. These cells will be individually fused ...

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