# All Questions

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### Finding all hazards in a small MIPS program

I have the following MIPS program: bne $zero,$zero, Label add $t2,$t3, $t4 add$t5, $t2,$t4 lw $t2, 0($t4) Label: add $t5,$t2, \$t2 ...
10 views

### Safe to turn variable speed AC motor on/off via wall switched outlet

I have a (high velocity air) dual AC brush motor pet hair dryer (details). (There is no heating element.) It's rated at 120 Volts 18.5 Amps. It has a rotary knob (listed on the parts page as a "...
64 views

### Heatsink on underside of PCB

I have prototyped some DC-DC converter modules, and they work well. However due to size, I don't have a huge amount of copper pour for them to dissipate their heat. I have used 2oz copper but the ...
16 views

### Can I run a DDR4 module at 50 MHz?

I haven't seen any restrictions about minimum clock, but I may have overlooked them.
14 views

### Can I make my own flight controller with following knowledge

I want/plan to build a basic quadcopter for the hobby. On the web, in most cases, everybody uses a flight controller like APM or PixHawk for example. I am a beginner in the embedded world and was ...
20 views

### Connecting balanced low impedance output with unbalanced high impedance input

I want to send the signal form my audio interface to the guitar pedal effect. I'll use interface's line out balanced output and plan to plug it in to the effect pedal which has high impedance ...
17 views

### Circuit Definition

This is a circuit that I've found in my old amplifier board. Experts please help me identify this circuit and please describe how it works. I am sorry for my crude drawing, but this is what I found ...
103 views

### Ident of a 10 contact RJ45 style connector with 8 + 2 contacts

I'm trying to find a plug that will fit into this RJ45 style socket. The top picture shows 8 contacts just as you would expect from a RJ45 8P8C style socket, in fact you can plug a standard ethernet ...
79 views

### Transfer function of an ideal op amp

This problem requires solving for V2/V1. My approach: R2 and R4 parallel reason: R2 has virtual ground and R4 is connected to the ground. Applied Nodal Analysis and got the following answer(...
248 views

### Transistor power dissipation rating

I'm trying to build the following circuit Except mine is a 24V ~20A (500W) motor, so I need to swap the components. I'm currently looking into transistors and I've stopped on the 2N6284 (NPN) ...
8 views

### Networked Control System

How to design an error co-variance matrix to tranmit data using optimal power between two ends viz. Transmitter and receiver?
67 views

### Simplest instruction set that has an c++/C compiler to write an emulator for?

I'm looking into writing a little software emulator, that emulates/runs instructions. Easiest would be to invent my own instruction set, but I thought it would be more fun if what I write an ...
71 views

### Lowest breakdown voltage diode, [on hold]

I'm looking for a diode which has the lowest forward voltage, about 1 mV or lower. I wanted to limit the signal amplitude to 1 mV. I would be very grateful for specific examples. The output impedance ...
16 views

### Variable Frequency Variable Amplitude PSU [on hold]

I’m looking for an adjustable power supply that takes 220V 60Hz AC and produces an adjustable RF power line (10MHz range) with amplitudes up to 500V. Where can I find these? I need something ...
16 views

### Reverse polarity protection for battery powered application

Im designing battery powered application and need reverse polarity protection. My system specs: 4.5v(3x AA batteries) in and system running on 3.3v. Im using MCP1711T-33I/OT LDO to convert 4.5v to 3....
203 views

### Using a 36V battery with step up converter for 48v kit

I have an e-bike motor ( bbs02 48v 750watts ) which requires 48v battery. I also have a 36v 13ah ebike battery. Opening the battery and changing cells connection to make it 48 takes a lot of effort. ...
46 views

### Is USB Vendor ID needed to sell custom USB-hub based on IC?

I'm about to make a hobby project - build custom USB hub fitting required physical/package dimensions and port positions. The main IC would be TI TUSB4041I, which is is 4-port 2.0 USB HUB (I don't ...
1k views

### Solar charging with a super capacitor buffer

I have a 20W 5V solar panel (real output more like 10W in bright sun). Would like to harvest as much solar power as possible to a power bank to power a bluetooth speaker (< 5W consumption). Bright ...
36 views

### MSP432+BLE+ Debugger interfacing

I would like to Interface a BLE to a MSP432 microcontroller in serial. The BLE has a inbulit Atmel controller. I have a firmware for BLE in keil. Intially I have flashed the firmware to BLE directly ...
385 views

### high current buck converter?

I am in the process of building a power bank with 18650 batteries for a trolling motor. The nominal voltage for this battery is 14.8 V. The motor specs are 12 VDC - 45 A max current draw. Now the ...
25 views

### RFID software development [on hold]

I would like to know how to implement my own RFID reader software. I have read that these readers do come pre-installed with their own software however the disadvantage is the cost. Hence it will be ...
231 views

### Will copper pour help on my single-layer PCB?

I have a PCB which contains one 20x4 LCD, eighteen 12x12 mm push buttons, and three LEDs. This board is connected to an Arduino Mega through a 30 cm long ribbon cable. Now during testing, I ...
19 views

### MSP430 MPU9250 MPU6050 I2C: After sending the address NACK

I have a problem with read from my MPU6050/MPU9250. Both are connected with AD0 to ground so both should have the address 0x68. With both sensors the same behaviour ...
31 views

### Why is LTSpice Bode plot disagreeing with a linear plot?

Here is a picture of an amplifier that I'm simulating using LTSpice. When I insert a sine wave of 0.01 volts and 314Hz as an input, I get this: The output is taken from the collector and is ...
56 views

### does my microwave oven have acceptable leakage?

I remembered that a microwave oven works on 2.4 GHz which is same as wifi frequency so I did a test for the leakage for my microwave oven, I put the oven's door in front of 2.4 GHz wifi router(line of ...
102 views

### If npn transistor switch is saturated, does base get galvanically connected to emitter?

Playing with Christmas lamp TRIAC, I got this question. Suppose some transistor is saturated, if gate current is >= 1ma, and I want to control it with 5V Arduino (or STM\PIC\etc) port. So I need to ...
45 views

### Change of variable from t to $\tau$ during convolution

I am not able to understand that in the standard convolution formula how we can change the variable from t to $\tau$. $$\int{x(\tau)\cdot h(t-\tau)d\tau }$$ Isn't this incorrect mathematically?
80 views

### Fender Telecaster guitar makes loud humming noise, stops when player touches strings/metal parts

I have a Fender Telecaster that hums loudly--much more so than other similar guitars. It's a standard Tele with single-coil pickups. The humming noise stops when the player touches the strings or ...
131 views

### Append Two String to LCD Using MikroC and Proteus

I tried to read EEPROM values and display that value with a string. This is my MikroC code: ...
97 views

### Ohm's law confusion

I've been trying to learn electronics stuff from this video series on YouTube: https://youtu.be/m4jzgqZu-4s At 1:07 in the video above, with the switch closed, both sides of the switch seem to be at ...
231 views

### What is actually sent/loaded to a microcontroller / STM32?

I see in all tutorials or sources, everybody creates a project in some IDEs and then loads code to the MCU again via those IDEs. What is sent to the MCU? Is it a sequence of binary numbers or some ...
20 views

### sequential I2C read from PU6050 with pic16F18877 different from expected

To save time and reading I copied a code block from a program found on the internet to determin the X angle of inclination. ...
46 views

### 4 Phase 5 Pin high speed motor driving (turbomolecular pump driver)

I just recently purchased a broken Turbomolecular pump from eBay and repaired it, now that it works again I need to build a low-cost driver for it. It has 4 Phases and normally relies on hall ...
39 views

### Wishbone B4 rule 3.55: Is this for a special case?

Rule 3.55 of Wishbone states: "MASTER interfaces MUST be designed to operate normally when the SLAVE interface holds [ACK_I] in the asserted state." I read this rule together with permission 3.35, ...
54 views

### Crystal's datasheet give load capacitance is 20pF, do I need external load capacitors?

I use external crystal for HSE of STM32F0. I plan to use 8MHz Cylinder Crystals. Datasheet of this crystal below Datasheet give crystal load capacitance is 20pF My questions: 1/ Do I need to add 2 ...
117 views

### Envelope detector circuits

Why do these circuits have different output signals, please explain in detail. And how does the envelope detector work?
16 views

### The generic carry formula of CLA

I'm trying to learn about the CLA (Carry Look Ahead). I found out that the first four carries are: I'm trying to build a generic formula for ...
39 views

EDIT: The exact issue is this, the ADC has a gain register (set during internal FS calibration and again at System FS calibration) and an offset register set during system zero calibration. The ...
19 views

### replace Miner controller board [on hold]

my miner controller board get crashed (S11 Antminer).. after many searches I can't find a suitable board for that but I found the S9 controller... my question is can I replace S11 controller board ...
27 views

### ccd with response “time constant” of less than 0.5 ns & maximum “radiant sensitivity” exceeding 10 mA/W

I'm building a Raman Spectrometer. The following specs are listed under the U.S. Strategic Goods list where export license is required for any electronic item to be shipped out of the country. Does ...
16 views

### Need advice choosing wiring configuration for combination pressure and temperature sensor

I am currently trying to purchase a combination temperature and pressure transmitter for a project, and it has an option to choose between a 3 wire or a 4 wire configuration. I have attached the link ...
89 views

### Thermal resistance - Temperature transistor

I have a transistor with Vsupply = 24VDC, VCEO = 45VDC, ICE = 20mA. How to calculate the delta T (rise in temperature) of this transistor. I would like to know what thermal resistance I may have at ...
739 views

### RC Lowpass Filter between Amplifier and ADC input

I have sensors (pyranometers that consist of thermopiles and measure sun irradiation) that ouput a low voltage signal so I need to amplify them using an instrumentation amplifier. I have chosen the ...
23 views

### Buck converter LC output filter contribution to phase margin

I'm trying to develop a better understanding of how my power distribution network can affect the stability and performance of buck converters, which has lead me to documents like this one. The main ...
110 views

### Distance required between two wires to avoid EMI

I am running 3 cables cables from a solar heater down to my apartment (around 12 meters), one to power an electric heater and water pump (around 2000 watts in total), one to control a 12V solenoid and ...
89 views

### Li-ion CR2 / 15270 voltage and charging circuitry

CR2 / 15270 Li-ion batteries normally come as 3.0v. I thought Li-ion and Lipo batteries were always 3.7v, how is that possible? Does it require a different charger circuit than normal 3.7v li-ion/...
31 views

### Need recommendation on SBC or microcontroller / ADC / other components for analog sensor and instrumentation measurement [on hold]

I am a civil engineer with minimal experience working with instrumentation and sensors, and RPis. I am building a small project, and I need a recommendation on a model of SBU or microcontroller to ...
97 views

### Switch module test circuit design

I am doing a project to make a test box that would test the switch module in the photo below. Please see circuit diagram below for inside of the switch. Please note this switch is not an ordinary ...
Edit: My primary objective is to learn the mathematical model to compute the load resistor $R_s$ to satisfy a given crystal's drive level, not just fixing the one instance below. I'm building a ...