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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 ...
10
votes
0answers
365 views

What is this weird EMV pin on my credit card?

I recently got a Venmo card, which is my first card with contactless support. I was looking at the EMV pins and noticed a very weird design. In the middle of the ground pin, there is this long, thin ...
8
votes
2answers
322 views

Looking for criticisms for a VNA-like meter I am designing

I would like some help from anyone who could let me know any flaws or improvements in my design they can find and help me reconsider any last minute design fixes before I send my new project off to be ...
8
votes
0answers
382 views

Convert analog piezo "transition" to digital signal

I'm trying to get what amounts to a knock indication into a microcontroller input from a piezo sensor. It's looking fairly good now at the fifth iteration, and about ready to provide digital levels ...
7
votes
0answers
317 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 ...
7
votes
1answer
4k views

Dual active bridge converter

I'm having issues calculating the power losses associated with the operation of a bidirectional isolated Dual Active Bridge DC/DC converter. The converter is controlled using Phase Shift Modulation (...
6
votes
0answers
83 views

Speed of compound wound dc motor

This is homework. Given a 500W, 200V compound wound motor with constant shunt field and a series field that varies with armature current, how do we calculate the change in motor speed. I know the ...
6
votes
2answers
2k views

How to calculate capacitor values in a Common Emitter amplifier?

Ok so I am designing a Common Emitter amplifier using a BJT and this has been driving me crazy for the past four days. Yes, this is for an assignment and I am not asking to have my homework done; my ...
6
votes
2answers
251 views

Rigid-Flex PCB Fabrication: Window opening vs slot opening

We had issue with one of the rigid-flex design cracking at the joint of Rigid and flex intersection. It is important to note that this is second batch of same PCB and PCB was not cracking in first ...
6
votes
2answers
507 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 ...
5
votes
0answers
63 views

Why duplex lap winding has twice as many current paths as simplex lap winding?

I found the statement of question on page 346 in the book "Electric Machinery Fundamentals, fifth edition" written by Stephen J. Chapman. When I searched for how duplex lap winding looks ...
5
votes
2answers
439 views

Low power tube headphone amplifier design

I have never worked or even listened to tubes/valves before, so its about time I did. I wanted a simple design to work with being my first tube project, and have found this from diyaudioprojects.com: ...
5
votes
3answers
225 views

How to properly step down the voltage of a DC+AC signal that then goes inside a pin of a PIC?

The reason of the question is because i don't know if this is the correct way of regulating a signal that goes inside the pin of a PIC that accepts a signal that goes till 3V3. In the following image ...
5
votes
1answer
426 views

PCB layout - ground plane clearance around and under a ceramic resonator

We are using Murata's 4MHz ceramic resonator (CSTCR4M00G53-R0) in one of our designs and request help in PCB layout design around the ceramic resonator. The below Murata's FAQs page suggests not to ...
5
votes
0answers
681 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
90 views

Phase shift near saturation mitigation in input stage amplifier -- How does this work, why does this work?

I'm trying to understand how this circuit works on the input stage to the 4192A Impedance Analyzer. Apologies for the quality... this is the best scan I could find. The design is furnished with the ...
5
votes
1answer
1k views

Why did this arduino burn out? SilentStepStick (TMC2130) stepper at 24V

I'm new to electronics. Attempting to bench-test a SilentStepStick stepper driver board, (based on a TMC2130) Using: Arduino Uno, a SilentStepStick driver board, a 0.6A stepper motor, and waterott ...
5
votes
4answers
1k views

32.768 kHz Crystal Troubleshooting

I'm at my wit's end trying to get a 32.768 kHz tuning fork crystal to work and I don't know what I'm doing wrong. First, some background: I'm using a 16MHz crystal in conjunction with an Atmega 328P-...
5
votes
2answers
3k views

How to calculate and measure motor constant for stepper motor?

I am working on a project using ST4118D30004 stepper motors and powerSTEP01 drivers. The ST4118D30004 is a bipolar stepper motor with 4 wire connection. While researching how to find the optimal ...
5
votes
0answers
135 views

Frequency locking for averaging resampling

Background I've done a long one-shot measurement of a periodic signal by an oscilloscope. Thus, I've captured around 250 periods of a signal. The signal itself is a pseudo-random binary sequence at ...
5
votes
1answer
350 views

Practical ESD protection without latchup

My understanding has always been that any CMOS I/O pin needs external ESD protection - since the on-chip protection diodes are only there to guard against ESD events during manufacture handling. ...
5
votes
1answer
635 views

Designing single fault safety into class I device

I'm trying to wrap my head around safety standards for electrical equipment. My device is medical, so for me section 8 of IEC60601-1 is what really matters to me, but it's kind of my understanding ...
5
votes
1answer
615 views

Interfacing TDC sensor (inductive pickup) to a microcontroller

I'm trying to do some diagnostics on a classic car (aircooled VW). In particular, I'd like to monitor a signal that flags the TDC (Top Dead Center) on every engine revolution. The signal is available ...
5
votes
0answers
416 views

Understanding EGSM-900 (LTE 8 band) electromagnetic spectrum

I am trying to fully understand the physical layer of the GSM standard. For doing that I am looking at the E-GSM-900 band (mostly used in Europe). In my country these frequencies has been assigned to ...
5
votes
2answers
883 views

LiFePo4 current limiter with supercapacitor in parallel

I am making a LiFePo4/supercapacitor-hybrid. Spike current draw can reach 300A for a few seconds. The LiFePo4 batteries I am using is rated for 100A max discharge rate. In order to make sure the ...
5
votes
1answer
481 views

MCU HIB pin only pulls Buck/Boost EN pin every-other Hibernation

MCU: TM4C1294NCPDT Buck/Boost Converter: TPS63051 Hib dedicated LDO: MIC5504-3.3YM5-TR I have a LiPo battery coming into the board, feeding both the TPS63051 and the MIC5504. Tiva's HIB pin is ...
5
votes
2answers
2k views

Schematic for a lipo battery bleeder overcharge protector

OK, so I am building a 12v (really 11.1v) 10000mah lipo battery. I am going to use it on campouts to run things like 12v fans and car chargers and run other high-current devices that couldn't be run ...
5
votes
0answers
253 views

Home made passive tablet pen

I have an old wacom tablet at home, its really big and I'd like to use it but I've lost the pen for it. It uses pens with passive LC circuitry. The board creats an EM-field (I can see it on my ...
5
votes
0answers
147 views

Testing strategies for testing a Scheduler

We have developed an in-house Scheduler which is based on Rate-monotonic scheduling. We have 6 tasks (5 actual tasks and 1 idle task). Our scheduler works on 1msec timer interrupt. Before sending it ...
5
votes
1answer
6k views

RGBHV (VGA) to YPbPr Converter and Waveforms?

Purely for hobby, I am working on an RGBHV (VGA) to YPbPr (Component) converter circuit for old games consoles modified to output RGBHV on a VGA cable. From the game consoles, the RGB signal is taken ...
5
votes
1answer
686 views

Thermal Modeling of 0805 Thick Film Chip Resistor

I recently got confronted with the question what peak/pulse power a standard 0805 thick film resistor can withstand. Background: We are designing a 2kW bidirectional DCDC converter. The Primary side ...
5
votes
1answer
281 views

What is the purpose of the 7805 output capacitor?

How does a cap on a regulator output improve transient response? Is this cap not more appropriately drawn next to the load where it is not being defeated by intervening trace inductance? Or does this ...
5
votes
1answer
538 views

Charge mode piezoelectric signal conditioning

I have a charge-mode piezoelectric dynamic pressure sensor (datasheet link) that I want to read a signal from. If you look at the datasheet it says the sensor outputs are in a balanced and floating ...
4
votes
1answer
115 views

Q: Homework - Past exam solution Is this the right solution?

I am trying to find Vo but I am not sure If this solution right? Is there a shorter path to find Vo? solution
4
votes
0answers
122 views

How to understand a complex diode-resistor function generator circuit?

I'm reverse-engineering a CRT anti-pincushion circuit and it uses a complex diode-resistor circuit to approximate the function X-k×X×Y², where X and Y are the deflection voltages. My question is if ...
4
votes
2answers
124 views

USB connector always reverse to connections on the IC

I'm looking to add an interface IC on to my PCB. The chip will interface through a USB B Micro connector. What I don't understand is why all the ICs I have found are designed so that the D+ and D- ...
4
votes
0answers
195 views

Cannot find what causes faults on DRV8353RH

I keep getting faults on a a new batch of ESC boards based on the TI DRV8353RH & Infineon IPT020N10N3ATMA1. Please consider: When starting a motor at 48V - 56V the DRV asserts a fault after ...
4
votes
0answers
68 views

Why is the imaginary part absent in the BJT gain calculation?

The gain of transistor Q1 was previously calculated in this post simulate this circuit – Schematic created using CircuitLab It was found to have a gain of about 2.92. Now I change the ...
4
votes
0answers
194 views

What is exactly modeled by 'transit time' in SPICE diode model?

I'm trying to find a precise definition for the transit time parameter in SPICE diode model. What I think is the official documentation for standrad Berkeley SPICE diode model says the following ...
4
votes
0answers
86 views

What keeps frying my RF switches?

Short version: What might be breaking the first sensitive component connected to an ungrounded 14cm UHF dipole antenna mounted 30' above the ground? Could it be related to static electricity? I have ...
4
votes
1answer
167 views

Bridge rectifier low voltage

Power supply for headphone tube amp gives me 10-12V lower voltage comparing to the schematic (my measurements are in red for amp under load). Current under load is about 70 mA. Using simple formula : ...
4
votes
1answer
121 views

Need help identifiying SOT23

I accidentally killed a transistor in my HP Elitebook 820 G3 and need help identifying it. I searched the internet for about an hour and can't find the code that ist printed on the component to buy ...
4
votes
2answers
104 views

automatic submersible pump actuation project

I have a project for automatic submersible pump actuation using a microcontroller. I've done for two voltages like 5 V and 12 V and its corresponding relay. Also, in each board there is a transistor ...
4
votes
1answer
103 views

Motor calculations for go-cart / go-kart

I built a basic wooden go-cart and I want to convert it to electric power, and my question is how to calculate the motor. I searched here and apart from this 24V 250W motors I can't see any similar ...
4
votes
0answers
198 views

Invisible magic components that spoil the Eagle preview

You know, after the eagle board design is finished, you can see the card on the preview screen. I'll show you two examples. There is no problem with one. The card is centered on the preview screen. ...
4
votes
0answers
108 views

Detection of CT secondary subsidence current

In utility power system protection we have a protection function called "breaker failure" protection. This protection is used to take appropriate action if/when a circuit breaker fails to ...
4
votes
0answers
150 views

Drift with Madgwick algorithm with fast movements

I am trying to correctly track orientation of a sensor with accelerometer and gyroscope using the open source Madgwick algorithm. The algorithm returns quaternions which represent the rotation between ...
4
votes
0answers
176 views

What is the use of second transistor in this circuit?

This is probably not a good title, can you suggest me a better one? I have this circuit above, and I am supposed to find its voltage gain \$V_{out}\over V_{in}\$. But I don't understand what use the ...
4
votes
0answers
249 views

Why DDR4 Specs recommend that Address, Control and Clock buses be referenced to VDD?

Micron's Technical Note TN-40-40: DDR4 Point-to-Point Design Guide, page 19, says (emphasis mine): Timing Budget Suggested practice is to look at the design from a timing budget standpoint to provide ...
4
votes
1answer
304 views

How can I identify a connector type?

How do I go about identifying an unknown connector, either from spec or measurement? For example, I've got a GM4632-730 DC motor, which unfortunately came without the cable (and to make things worse, ...

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