# All Questions

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26 views

### Using LM2596 step down with LiPo

i'm doing a project with esp32 (3.3v), dht11(3v-5v), soil sensor (3.3v-5v the cheapest Chinese), nrf24l01 (2.6 - 3.6v). I'm using lifepo4 right now (3.32v) but when the battery drop about 3v, soil ...
44 views

### Long term health effects of a gsm modem [on hold]

We all use internet through our mobile phones hence gsm infrastructure. I know the radiation exposure is higher than wifi. That's why I preffer wifi over mobile whereever i can. However I'm currently ...
41 views

### Differential pairs or single ended signals for 1m cable

I have one control board and 3 additional boards for the power electronics, that send and receive data from the control board over a distance of ~1m (3ft). All signals are single ended. I have to ...
36 views

### Constant power load SPICE model

I would like to create a SPICE model for a constant power load. I'm guessing that would involve using an equation to dynamically adjust the model's resistance based on the applied voltage. How do you ...
3k views

### why neutral does not shock. how can a neutral be neutral in ac current? [duplicate]

When I probe my city mains with one probe in the live and one in earth (which should be 0 volt) it shows a voltage of around 250v. But when I probe the neutral and the earth it shows no voltage. I ...
11 views

### connect multiple source pin together to power signal in Eaglesoft

1.according to PCB shown below, I have a bunch of MOSFETs with HSOF package with 7 pins of source for each and failed to connect EVERY pin to the connector, in other words, when routing the source ...
31 views

### Bootstrap capacitor calculation - Which formula should I pick?

In order to calculate capacitance of bootstrap capacitor, I searched around and found two different formula from Ti and Infineon. The Ti version states: while Infineon version say: I think the basic ...
51 views

### Electrical Standards - Earth Wire at Low Voltages?

I got a question about safety standards: I'm designing a consumer device and I'm not sure whether I need an earth wire. I have an AC-DC converter plug that outputs 5 V and up-to a maximum of 1 A ...
23 views

### On/off circuit from single (NO) momentary push button with emergency off from another (NO) momentary push button using a relay

I'm trying to have a failure proof power off from a normally open momentary push button, which I am going to call it S2. What I mean as failure proof is that S2 must turn power off. So, preferably no ...
18 views

### Choosing a damping factor in a RLC Low-pass filter

I have some basic understanding of what the damping factor from control theory. However, I don't know how I should choose it. We have 24VDC which goes through a input power filter (RLC low-pass ...
19 views

### How do we determine the roots from a Routh-Hurwitz array?

I know that we can determine the roots on the right-half plane by counting the sign changes in the first column. However, I'm unsure how to find the roots on the left-half plane. Is it the same as the ...
46 views

### How do I use one output to block an input until that output turns off?

I have a device with two inputs, each with an associated output. I require a means of allowing only one input-output circuit to be active at a time. If a second input is activated while the other is ...
39 views

### Charging a capacitor in Eagle SPICE

I'm trying to learn the basics of Eagle SPICE simulation with a simple capacitor charging circuit. My netlist is as follows: ...
30 views

### Trying to understand Battery Chargers vol.2 [duplicate]

The answer by Bill dubuque was very helpful and got me to read the complete datasheet of MCP73831/2, but there is one thing from the datasheet that I don't fully understand and is the cause of lots of ...
44 views

### Corroded PCB from Rechargeable NiMH battery

This NiMH battery began to leak battery acid onto the circuit board / PCB below it. Some of that acid ran down one of the wires connected to the battery and pooled up at the foot of the plug where it ...
62 views

### Chua's circuit producing unexpected waves?

I have built the Chua's circuit in the following diagram: I then hook it to a soundcard oscilloscope. It produces the following wave: Such waves doesn't change no matter how many times I repeated ...
24 views

### DIP temperature Sensor with serial port [on hold]

I am looking for a temperature sensor which is in for of DIP suitable for breadboards and serial communication that is usable for Arduino. I am not after a resistive or an analogue sensor. I am not ...
42 views

### I need help identifying two passive SMD components from [ GoPro Hero+ ]

[ This is the bottom side of the GoPro PCB. I marked the components I need identifying. I assume they are either capacitors and/or resistors, but I need confirmation.
37 views

### How can I know the number of units consumed by each A.C. in a home

The question is fairly simple. I have three air conditioners in my home and the bill for their electricity consumption comes combined as only a single meter is installed. My question is Is there any ...
90 views

### How is power demand variation of supercomputers handled at power plants

When a supercomputer is given work and all processors begin work there would be a large spike in demand. Do large supercomputers communicate with power stations to notify them of demand changes from ...
51 views

### Is it intuitively correct to think of voltage as a “propellant” force?

From my understanding voltage is an electromagnetic force that creates current by exerting a force on an atom that causes that atom to transfer one of its valence electrons to the neighboring atom. ...
32 views

### Correct procedure to identify a component and obtain the datasheet

I'm not sure what should be the correct procedure to obtain a component's datasheet starting from the component's package code. I searched in the other questions, but I found mostly people asking ...
46 views

### LEDs flicker when I move my circuit

I'm building an LED driver circuit, CD4504B and TLC5916 controlled by a Raspberry Pi: simulate this circuit – Schematic created using CircuitLab I'm finding that sometimes when I move the ...
34 views

### Normally Closed Negative Output, Positive Input Relay

I'm attempting to wire up my remote start in my manual transmission vehicle to ONLY start when the vehicle is in neutral. The way that the transmission works is like this: When in neutral, resistance ...
39 views

### Why does the common collector specifically have a high input impedance?

When looking at a chart comparing different BJT amplifiers, the common collector/emitter/base, it is usually said that the common collector has a high input impedance, therefore it is suitable for use ...
121 views

### NPN Transistors Not Working When Emitter Is Grounded

I'm trying out transistor logic for the first time using PN2222 transistors that came in a kit that I got from Amazon. I've been running into some problems with making a basic NOT Gate (as shown in ...
51 views

### Cleaning procedure for electronic tools and equipment?

I recently had to work from an old building which was in poor repair in order to get access to three phase power. I stripped down the room etc. so that there was a bare concrete floor but still after ...
36 views

### Phase noise of a digital PLL

I assume the reader is aware of how a DPLL works. The DPLL oscillates with a frequency of $F_{out}$. The DCO free running frequency is $F_{free}$. In the model of our DPLL we've only considered ...
58 views

### What Amplifier for Piezoelectric Ultrasonic Transducer?

first post here so feel free to point out my shortcomings. I am interested in building an Ultrasonic device utilizing two Ultrasonic piezoelectric transducers to create a standing wave between them ...
145 views

### What are these wiggly USB 3 traces on my motherboard?

I was taking a look at my motherboard, and I noticed the above traces on the USB 3.0 ports. A bit of prior research: The C34WH IC is probably a SN74LVC2G34 Dual Buffer Gate. Unclear what chip the top ...
37 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 "...
56 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 ...
46 views

### Can I make my own flight controller with following knowledge [on hold]

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 ...
75 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. EDIT: The module is a Crucial CT4G4SFS824A, based (this is an informed guess) on 4Gb Micron 512 Meg x 8
24 views

### Networked Control System [on hold]

How to design an error co-variance matrix that utilizes optimal power to transmit data/information through a fading channel between two ends i.e., Transmitter and receiver?
25 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 ...
59 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....
133 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 ...
43 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 ...
32 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 ...
28 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 ...
1k views

### What is the simplest instruction set that has a C++/C compiler to write an emulator for? [on hold]

I'm looking into writing a little software emulator that emulates/runs instructions. The easiest would be to invent my own instruction set, but I thought it would be more fun if I write an emulator ...
101 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 ...
18 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 ...
22 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 ...
35 views

### sequential I2C read from MPU6050 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. ...
64 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 ...
52 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. Update: For this Stellarnet Sony ILX511 CCD. https://www.stellarnet.us/wp-content/uploads/ILX511.pdf What is its response “time constant”? How do you understand ...
### 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?