# All Questions

117,745 questions
9 views

### Offsetting Voltage from 2.5v to 0 volts without Effecting Gain

I'm trying to digitize a Hall Sensor whose center voltage is 2.5V and the gain it's output is 1.5V to 3.5V, or ±1V. My digitizing card's center voltage is 0V and I would like to get the full range of ...
7 views

### 5 V from power bank not constant when supply circuit

Now I'm working on my project which contains Arduino, LCD, electromagnetic lock, 6 channel 5v relay and 500V isolated converter. My project was designed to power by using a power bank. Now I use eloop ...
12 views

### How do I wire in a capacitor into an LED circuit to eliminate a flicker issue? [migrated]

I have led running lights on my truck (with a resistor already inline) and am encountering a flicker issue ONLY when the engine is running. I was thinking a cap would fix it.
14 views

### +24VDC to 5v converter - does the positive make a difference? [migrated]

I have a fairly general question, but cannot seem to find an answer to confirm my thoughts. I have a garage motor door, and on the top has 4 terminals - 1 and 2 for a switch button to open and close, ...
51 views

### Lead Contamination in house after touching solder [duplicate]

I may have accidentally touched my laptop and keyboard and mouse and maybe my desk after soldering the one time I did and was wondering if it's contaminated with lead and how to clean/dispose of it if ...
17 views

### Tripping a circuit breaker when using a half wave rectifier

How does a half wave rectifier or phase control dimmer affect the triggering of a circuit breaker? For example, if a 20A resistive load was on a 15A breaker with a half wave rectifier. Now average RMS ...
5 views

### Deriving state table /equation confused

A sequential circuit has two JK flip-flops A and B, two inputs x and y, and one output z. The flip- flop input equations and circuit output equation are JA = BX+B'Y' KA = B'xy' JB = A'x KB = A +...
22 views

### Cheap switch alternatives to 9PDT for DIY USB sharing switch

Forgive my ignorance as I am a a sculptor trying to learn as I go. Any direction is welcome. I apologize as I know this question is probably a bit simplistic for this forum. All USB 3.0 sharing ...
12 views

### 220v universal motor Arduino control

I bought a 220v 100w sewing machine motor to use it in a project Firstly I thought that the motor works only on ac (because there is 220v written on it) and just for try I gave it 30v dc and ...
40 views

### Single transistor IR repeater

I need the IR repeater to pass IR (TV and so on) remote signal to remote devices in some box (pass the IR signal from outside the box). So, I bought a cheap IR repeater on single 2TY transistor, 4838 ...
265 views

### VHDL: Why is it hard to desgin a floating point unit in hardware?

Floating point calculation basically involves representing units in a scientific notation and then deciding how many bits to devote to the manitssa and exponent. Therefore, all calculations involving ...
156 views

### Which values for voltage divider

I just learned about voltage dividers and how to calculate the relative values for the resistors to use. For instance, to go from 5v to 3.3v I could use a 1 kohm and a 2 kohm resistor. However I could ...
24 views

### Replacing a 3-wire piezo buzzer with a relay?

My 9v water sensor alarm uses a 3-wire (M, F, G) piezo buzzer. Instead of a buzzer, I'd prefer wiring a relay to activate a 12v water pump. Is this possible, and if so, which leads should I use? ...
21 views

### Down counter using 4510 IC

So i wanted to create a counter that counts from 59 down to 0 using 4510 IC component, so i created simulation in Proteus software. This is what i came up with: This circuit works perfectly fine ...
61 views

### Johnson-Nyquist noise for a lossy inductor?

In searching the internet for thermal noise on an inductor and I'm not finding much on the basics for a real lossy inductor. I'm interested in thermal noise for a fixed inductor in a surface mount ...
44 views

### Epoxy Resin Molded vs Hermetically Sealed Metal Can Packaging for LEDs and Photodiodes

Between epoxy resin molded vs hermetically sealed metal can packaging for photodiodes and LEDs are there any relevant functional differences I should be aware of when selecting between otherwise ...
40 views

### to calculate the voltage divider resistor for transistor

My question is how to calculate the voltage divider resistor (R1 & R2).I have found that Ic=20.8 mA ,hfe=290,Ib=71uA.I'm using the transistor bc847b;the voltage divider network acts as a switch to ...
16 views

### Project involving the Texas Instruments TAS5720 amplifier - Power Requirements

The Google Home Mini uses the TAS5720 amplifier with a power supply which delivers 5V DC, 1.8A. From the datasheet it looks like this amplifier can deliver 20 W at 0.15% THD Continuous into 19 V / 4 Ω....
40 views

### What will be Resistance for maximum Power transfer from network A to network B?

simulate this circuit – Schematic created using CircuitLab Can we apply Maximum Power transfer theorem if we are given two networks both with voltage sources. In solution it was said that for ...
32 views

### How to know when the resault of subtraction is incorrect in a 4 bit binary subtraction circuit?

This is an image of a binary subtractor for unsigned numbers. Some times the output of binary subtraction is not correct and needs to be complemented to give the correct answer, how can I find out ...
55 views

### What is the difference between G(s) and H(s)?

During my research to understand transfer functions, i've come across two main notations: G(s) or H(s). But which one is correct? And why isn't there a standard notation used for the transfer function?...
27 views

The markings are: 1112 1Z The package is 2010 (5025 metric). Any clues will be much appreciated.
48 views

### USB Type C 3.1 PD to get DC20V output

I have a USB Type C notebook charger. I know it can supply 20V with 2.25A for my notebook. If I have a type-c breakout board, like this: https://www.ebay.com/itm/USB-3-1-Type-C-Female-to-Female-pass-...
50 views

I know this question has been asked many times before, however this question differs in the use of an uneven set of capacitors. I'm replacing the crystal on an old computer. The original symptoms ...
34 views

### battery fully discharging [duplicate]

My goal is to use my laptop, a pioneer dj controller and 2 krk rokit 5's (50W class-AB amplifier boxes) for a party all at the same time for about 6-8 hours in a place without access to grid power. ...
54 views

### Using a capacitor instead of inductor in a switching regulator, and viceversa

Contextualizing more: In a switching topology, and I am butchering it now, the inductor gets "charged", and eventually will keep an amount of energy "just enough" required for the load. This is ...
28 views

### New consumer unit and MCB calculations

I am planning on running a new circuit from my current board to a new unit in the loft that I am turning into a mini studio. I am trying to work out what Amp MCBs I would need, however am not sure I ...
13 views

### LG G6 Phone will sometimes charge ONLY using powerblock?

About once every six weeks my LG G6 throws a wobbler. The phone will not charge up using its mains adaptor. The only way to get a charge into is by using an Anker power block. Then it charges up fine....
20 views

### First-order hold interpolation in matlab

I have a sinusoidal signal x(t) sampled with period 1/fs. The result is the discrete signal x[n], where x[n]=x(t)|t=nT. Then I perform an upsampling of factor, let's say, 8 to increase the sampling ...
65 views

### Why would I use triangular solder jumper pads?

My PCB layout program of choice - Kicad - has footprints for normal rounded solder jumpers; but also triangular ones. What benefits, if any, do the triangular ones offer? Or is it a purely aesthetic ...
59 views

### MAX 485 performance

I wanted to test the performance of MAX485 drivers. I set up one driver and one receiver 2-3 meters apart. A 100 Hz square wave was being sent down the line. Roughly in the middle of the cable I put a ...
26 views

### Using a 7.4 V LiPo Battery for an Arduino Feather 32u4

I am working on an Arduino project at the moment, with the following board: Adafruit Feather 32u4 And it says I need 3.7 V of LiPo to power it. However I also have a valve that I want to open and ...
9 views

I'm using Adafruit 16-Channel 12-bit PWM/Servo Shield with Arduino Uno controller In setup() I have a number of default positions ...
15 views

### Producing Bi-Phasic Constant Current Pulse using L293 IC

I am trying to convert a current source output into the bi-phasic pulses. I thought maybe using L293 IC might help to change polarity of the currents. Here is the picture of design: as can be seen ...
16 views

### FG servo motor speed issues

I have been trying to get a 40-year-old turntable back to life, with relative success until now. Everything works fine but for an intermittent issue with the motor. The motor has two modes (for 33 1/...
33 views

### Is this an antenna connector?

I have seen 3 connectors in the image ABOVE in my 4G hotspot's motherboard, what are they ? I know these are not GPS because no need of GPS in a 4G hotspot. All of the 3 connectors are facing downward ...
36 views

### Inverting OP AMP SLEW RATE

I'm trying to do a question that requires me to design an inverting op-amp in multisim and find the slew rates in different scenarios using the OPAMP_5T_VIRTUAL operational amplifier model found in ...
33 views

### What current should I choose in bench top DC power supply?

Most of the time while I'm doing my university projects, I find that only voltage requirements are given for building a circuit, and how much current I should supply from a bench-top DC power supply ...
43 views

### Detect an unknown communication protocol and read data on it

We have old type textile machinery in our factory. (open end machine) on the machine's screen is showing the operating efficiency of the machine. Under the hood, When I follow the cables, the sensors ...
75 views

### Understanding a PNP/NPN LED schematic

I bought and soldered a dirt-cheap flashlight kit from China. I'd like to understand how it works, though - specifically, why it uses a combination of a PNP and an NPN transistor (schematic from the ...
41 views

### small party without power [on hold]

I am considering throwing a little party during my vacation however this will be in a place without direct access to power... My goal is to use my laptop, a pioneer dj controller and 2 krk rokit 5's ...
36 views

### Distance between UART and I2C bus

I create a board with two bus: UART and I2C. Now I am expanding the connection terminal, which has the following contacts: RX / TX / SDA / SCL / + 5V / GND. The question is, do the I2C and UART buses ...
32 views

### Where to add RF power amplifier

I am trying to make a SX1262 circuit using this schematic, I have the values for the passives from the BOM already. But I do not understand the schematic very much, where would I place an rf amplifier ...
36 views

### Can a Variac be modified to output higher voltages?

Since variable transformers can be had quite cheaply these days (under AUD 45 / USD 30 / EUR 27 today for a 500 watt one through eBay from China) they are cheap enough to experiment with. I bought ...
32 views

### Transformers: Short-circuit test

In a short-circuit test where the secondary winding is short circuited, how come the primary voltage isn't zero (in real life) when it should ideally be zero?
26 views

### How to calculate R1 and R2,? How do Mosfet IRF540 and ESP work in the circuit

So the 3.3V PWM signal from ESP is sent through R2 to the Gate to breakthourgh the Vgs(th) to make Mosfet ON, and the author of the circuit say Gate is pulled high to 12V by R1. But I don't understand ...
32 views

### Can I use a Ku band satellite dish for Wi-Fi?

Satellite TV works at 18-24Ghz and WiFi at 2.4Ghz, will a T.V dish antenna work for WiFi? Diameter of the dish is about 60-90cm
27 views

### Reading signal from 190v magnetic pickup

I am using a magnetic pickup to detect the phase and RPM of a rotating assembly. The magnetic pickup produces a pulse once per rotation when a ferrous interrupter passes the pickup. Dependent on the ...