Unanswered Questions

10
votes
0answers
143 views
+50

How does the CMRR of difference amplifier ICs change over time?

When designing precision analog circuits, I often come across parts which seem to be more than accurate enough for my purposes, but where the datasheet does not specify how key parameters will change ...
9
votes
1answer
248 views

Digital data coming out of a cell phone headset mic?

I want to connect a sound board / mixing console / whatever-you-prefer-to-call-it to the headset jack of my Motorola Android phone. I know the typical TRRS pinout of Left/Right/Ground/Microphone, and ...
8
votes
0answers
494 views

Unable to get bootloader working on custom PCB with AT32UC3L

I have designed a PCB for a client recently, everything is fine with the hardware and software (application is working as it is supposed to). Now we are facing the need to update the program inside ...
7
votes
0answers
141 views

Very intermittent power MOSFET failure

I am working on a very spotty motor failure (I am not the designer). We have a wound armature which is switched by power MOSFETs. These are driven by a FET totem pole type FET driver. When the ...
6
votes
0answers
347 views

Signal Flow Graph for electrical circuits

First of all, sorry if my English is not the best. I am a student and my question is about finding the signal flow graph for a simple circuit. I found the above formula for a \$k\$ node having ...
5
votes
1answer
198 views

NOP instruction after branch on ARMv7 Cortex M3

I'm interested, why for Cortex M3 microcontroller (stm32f103) compiler sometimes generates a NOP instruction after branch. And why it sometimes doesn't. For example: ...
5
votes
2answers
414 views

Miniature wireless distance sensor

I am novice in electronics, so please bear with me. I am searching for a small distance sensor (as small as possible) that I can use to measure a distance between 0 and 30 cm precisely (precision ...
5
votes
0answers
171 views

Implementation of AES algorithm using Systolic architecture

I need to generate a VLSI Systolic array to implement the AES encryption algorithm with key length of 128 bits. Following are the possible ways : Systolic for Key expansion Systolic in MixColumn ...
4
votes
2answers
83 views

How to implement critical sections on ARM Cortex A9

I am porting some legacy code from an ARM926 core to CortexA9. This code is baremetal and does not include an OS or standard libraries, all custom. I am having a failure that appears to be related ...
4
votes
0answers
48 views

USB multiplexer - swap pins?

I want to use the USB 2.0 multiplexer TI TS3USB221ARSER. But on the PCB the D+ and D- pins of one connection are crossed (see attached image). Is it okay to change the D+ and D- pins on all sides of ...
4
votes
2answers
79 views

Is it possible to determine load on a stepper motor when stopped

Is there a way that the torque on a stepper motor can be determined without some kind of additional force sensor. Additional electronics such as current shunts etc would be acceptable. I would like ...
4
votes
1answer
93 views

Secure signals on boot time to prevent unwanted operations

How can I be sure that at boot time my module won't get random values to it's control signals and write to an address* before I reset the module? *(or anything that shouldn't be done before reset) ...
4
votes
4answers
148 views

Calculating current draw from a battery using voltage and time information

Is it possible to work out the current or power a device is drawing/using, based on the following information: Maximum capacity of a battery (48 Ah) A table of voltage readings over time (starting ...
4
votes
1answer
149 views

How to disconnect voltage from BeagleBone Black expansion pins?

I'm trying to create a cape that will safely power my BeagleBone Black from my car's electrical system. The design I am using is based on the one from this answer. The circuit there suggests a simple ...
4
votes
2answers
71 views

What certifications are required to sell a home kitchen appliance in the USA?

I have read what the possible answers might be however someone may have had a recent experience dealing in this area. If I wanted to sell an automatic soup maker in the US (please keep in mind that ...

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