# All Questions

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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 ...
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620 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 ...
651 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-...
3k views

### Calculating the ESR of Capacitor

I try to calculate the ESR of a capacitor. I checked this datasheet: http://www.farnell.com/datasheets/2245214.pdf?_ga=2.167304311.817060034.1534770853-676261198.1531404202 I can see from the ...
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### 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 ...
883 views

### Efficient 60v to 12v DC-DC

I'm on the process of building a new version of my ebike electronic systems and I'm searching for a way to lower the voltage of the battery (13s = 54,6v fully charged) to 12v/5v for the accessories ...
8k views

### How can I model this common mode choke in circuit in LTspice?

How can the common mode choke in below diagram used in LTspice? By an inductor or transformer? How should be the circuit drawn in LTspice? I want to use this to filter out CM noises for single ended ...
747 views

### Is it possible to use Microchip's ZCD (Zero cross detect) circuitry in an isolated SMPS?

Let's say you have a device which is fed by AC line voltage and features an isolated SMPS. The switcher outputs 5 VDC, and that powers a PIC micro. I'm curious how is the Microchip's ZCD (Zero cross ...
6k views

### Altium Designer: Polygon does not connect to the pads on the same Net

I'm trying to put a plane shield using polygon pour and I realized that some object is not connected to my polygon. In the picture below it is clearly seen that the GND through hole is not connected ...
353 views

### What is the 3D radiation pattern of this chip antenna?

I know that the 3D radiation pattern of an antenna could be found by knowing the xy, xz and yz plane cuts and vice-versa. This process is pretty straight forward for a dipole antenna which has a 3D ...
651 views

### Lifepo4 current limiter with supercapacitor in parallell

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 ...
425 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 ...
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### Help with deciding my layout for EMC tests and SI. Different alternatives

I am thinking of what way would be the best to layout my system in order for it to have the best SI and pass EMC tests. My system consists of two PCBs joint by a flat flex cable (up to 7cm) and these ...
262 views

### Setting up T2080 to FPGA PCie DMA

I'm doing an FPGA design using a T2080 MPC interfacing to an Altera Cyclone V FPGA. The goal is to use my FPGA to pump 2 other FPGAs on the same board. I need to create a scheme that allows the ...
217 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 ...
130 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 ...
112 views

I tried the following circuit but the LEDs for me are always on and don't blink, i checked connectivity, changed capacitors and tested transistors but same problem. what could be the issue? edit: ...
103 views

### Tuning of a PID loop for heater element

I built a controller for a soldering iron (JBC C245/C210 specifically), which can supply up to 60W of power to the iron. I have a temperature control loop that runs at 10 Hz, which I am trying to tune ...
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### 36x LED 5730 in series: diodes burnt when LED driver (based on BP9833A or MT7854BD) powered up

Background: I have 18W, 36 LED lamp fixture which I cannot change. Originally it has 2x parallel 18off 5730 LEDs and 300mA driver. It works for some time, but diodes starts burning. I thought that ...
172 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: ...
700 views

### Why does the UPS mode of an inverter have faster switching times?

Of all the sinewave inverters I have used, they contain a switch at the back labelled Normal and UPS. When you put the inverter in normal mode, there is some 40-50 ms switchover time, enough to make ...
169 views

### Feedback Topologies

This is my homework problem. I tried to solve this problem but i got it wrong. Here is the problem: As it is clear from the circuit that we are taking voltage at the node V0 and some fraction of ...
215 views

### What is causing this weird effect with aluminum?

I grabbed an LED and then scraped an aluminum plate with a pin, and it turned on at some points, at first I thought it was electrified but it wasn't, then I tried with another aluminum plate and it ...
113 views

### ATTiny85 clock speed problem

Using an ATTiny85 and an Arduino loader I created a simple device for turning on an exhaust fan based on a light sensor. The ATTiny85 turns on the fan after activating a warning light and sounding an ...
135 views

### Non-inverting op-amp saturating incorrectly

Background Hello, I'm trying to amplify an audio signal using an LM324N in a non-inverting configuration. I'm not trying to build an audio amplifier to drive speakers, I just need to amplify it a bit ...
454 views

### Adding foot control to tig welder

I've got a simple tig welder that uses a switch on the torch to start the welding current and a potentiometer on the front panel to set the amperage. Many welders make use of a foot pedal to start te ...
254 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 ...
229 views

### Modeling scalar control of PMSM

I have met with a scalar control algorithm for a permanent magnet synchronous motor. I haven´t heard about it before so I decided to develop a dynamic model to further analyze this control algorithm. ...
700 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: ...
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### How can I reshape this PCB antenna so that I can still use it with the given circuit?

I'm borrowing the RF design from the MICRF114 Development Kit. Here's user guide- http://ww1.microchip.com/downloads/en/DeviceDoc/50002433A.pdf The circuit I'm using is on p. 35 and the antenna ...

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