# All Questions

118,042 questions
6 views

### Immediate Rain Detector

The Problem: I tend to open my bedroom windows so that the natural breeze can pass. This is great for cooling but not great when rain falls. If rain falls heavy enough, even if it falls for 1 minute ...
6 views

### Is there an economical 2-3 RPM 120v motor with speed control? Or what components could I use to achieve that scenario?

I've got a mechanical design for a piece of catering equipment and I need to figure out a way to achieve some variable speed control for a slow RPM motor. This is a direct drive application (imagine ...
20 views

### Fusing electronic platforms into one IC board

I have an insane goal whose possibilities id like to discuss. To start with I am interested in three different electronics platform for edge computing: Edge computer: Like Raspberry pi or Intel ...
28 views

### Working on a design that requires a specific kind of physical switch

The switch my design needs behaves like the picture below. The user would slide the switch to the right to activate it and the switch would return to the left automatically, I assume by some kind of ...
11 views

### how the battery behaves in this diagram

My question is this. I'm using this ic mppt SM72445 along with a 250 watt solar panel, mppt output configured to 50.4 or 51 volts, 12-cell lithium-ion battery pack and bms, if the load is less than ...
34 views

### What are the ways to automate work of an electric motor? [on hold]

I need to develop a system which can make an electric motor to run for 3 second and run reverse for another 3 second and do this cycle for continuously and automatically for days. The motor should be ...
46 views

### What kind of plug is this?

I'm trying to figure out what type of plug is this. According to this site it is most similar to type A, but the blades are spaced only 10mm apart and they have the same size. According to here one ...
29 views

### Is there any physical limitation to cell carries sharing the same frequency?

Currently in the U.S. certain companies are granted leases on certain frequencies for cell phone communication. I was discussing with a friend how this allows a company with a lower frequency to get a ...
22 views

### I have a motherboard with HDMI output. What display for it needs I2C or SPI or another? [on hold]

How i can check compatibility? What parameter is responsible for this? I want to connect the display (for example from smartphones phones). I want find it on stores, but i dont know what will work.
27 views

### How make a pulse acquisition from an electrical meter directly into a raspberry pi?

I would like to acquire pulse informations from a french electrical meter. There is a picture of the outputs of this electrical meter. These pulses vary in frequency and after acquisition, we can ...
56 views

### How to measure this component

I want to know how to measure this components in the attached picture. If I'm right they are beads. The second one the brown one I thought at first that it is a capacitor but I can't measure its ...
30 views

### Solid State Relay is giving off voltage even when turned off

I'm currently creating a circuit according to this schematics i made. I have removed some irrelevant parts for simplification sake. The SSR in question is a 861SSR210-DC-1. When 5v is applied between ...
28 views

### Current consumption by 3-6V DC water pump [on hold]

If I use a submerisible pump of 3-6V DC and interface it to a controller via L293D. What will be the current consumption by pump? How should I calculate it?
56 views

### What are these tiny ports on my usb internet dongle? [on hold]

My vodafone usb internet dongle has these two tiny ports in the side with two small covers with a tower symbol on it. Are these by any way antennae connection ports?
63 views

### Matrix of small incandescent lightbulbs - problem with buzzing

I am prototyping a circuit for controlling matrix display of small incandescent lamps with Arduino (each lamp is 6.3V 0.3A). I designed the circuit in Yenka and built it. It is composed from 3 types ...
93 views

### What does this symbol on the box of power supply mean?

I always see this symbole behind electronic devices. A close-up image of the symbol: What does it mean?
25 views

### Hybrid library vs normal one

We use Orcad and we want to update our libraries. When we place a part and want to rotate it,we don't like the layout of the labels(names,values etc) and thus have to manually reposition them. It's ...
92 views

### 2000A current sensing using STM32

Is there any chance to read 2000A using STM32? I searched the Internet for low-value shunt resistor but nothing found. maybe some kind of current transformer could do the job!! any help will be ...
33 views

### Is it convenient to use a buck converter on a RS-422 communication board?

I am working on a PCB design with STM32 MCU. On the PCB there will be 2 MAX490 transceivers and one bluetooth module. Communication speed will be 921.6 Kbit/s for all communication elements. ...
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### High resistance, no current. What's the point of a potential then?

I am referring to this example: Why does it matter that the IC has a high resistance? What does this do for/to the IC? If there is a potential but no current, what is the point of using the IC when ...
65 views

### Why does this laptop adaptor have two metal shields with different thicknesses?

Yesterday, I opened my laptop adaptor to learn something. First off, faced to this kind of shielding: There are two shields that cover the circuit. A thick shield which is covered by a thin shield ...
38 views

### Where better to pull the NTC thermistor? To earth or VCC?

I have a NTC thermistor, resistance 10k. In various examples, thermistors pull either to the ground or to the VCC. The question is, is there a difference and what is safer?
21 views

### How to constraint clock on the GPIO of FPGA

I want to implement the JTAG protocol with Verilog HDL in FPGA. The TMS and TCK signals are all connected to the GPIO pins of FPGA, not to the dedicated clock pin. TCK's rising edge is almost aligned ...
23 views

### Vector Control & Slip

I know slip in induction motor determine the current and torque but the point I want to ask, when controlling with vector control it is said stator and rotor flux is always kept with 90 degrees apart ...
55 views

### Is this IR LED driver circuit with a transistor OK?

I am making a custom IR array board with a custom Arduino (only ATMEGA328 and necessary components.) So please tell me will this be fine or if I need to make some changes. IR LED = 940nm, continuous ...
53 views

### How to use libraries with delays inside within a time critical STM32 HAL application?

I want to use a library for an LCD for STM32: LiquidCrystal, and possibly some other libraries. I noticed this library is full of HAL_Delay calls, not only during initialisation but also during ...
35 views

### Shockley equation for diode series

I'm currently using the Shockley equation and a Newton-Raphson solver to find the current of a diode. I remember there's a variation of the Shockley equation that can be used to calculate two diodes ...
69 views

### Connect 10 LEDs using 5 volt current

I have 10 yellow-colored LEDs and ten 220 ohm resistors. I don't have any power source except the Arduino's 5 volt itself. Is it possible to power all the 10 LEDs using the 5 volt equally? Or will ...
65 views

### Design a Circuit with Zero-Order Transfer function H(s) > 1

I know that if I do 2 1K ohm resistors in series, I can just do a voltage divider to get Vout/Vin = R2/(R1+R2) = 0.5. But if I want to get a transfer function of 3, what components would I use?
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### Probing with oscilloscope causes current drop

We are testing a fabricated chip with expected output current of around 4mA which is then used to charge a button cell. The input is from a PV cell. However, when we attach an oscilloscope probe onto ...
41 views

### Output impedance of a series shunt feedback amplifier

I am trying to find the output impedance of a series shunt feedback amplifier by converting it to a two port network. I know the input impedance: Ri=ri*(1+A.β) But I dont know how I should find ...
48 views

### how a battery behaves in parallel to the charger with a shared load but with a voltage difference

how the battery behaves in this diagram how a battery behaves in parallel to the charger with a shared load but with a voltage difference
56 views

### Transformer question regarding efficiency

Due to the question being discussed in length on the comment section, I would like to address my question further with a new post linking from the discussion here: Transformers confusion with output ...
37 views

### Joule Thief Modelling

I Try to use a joule thief circuit to harvest energy from almost die battery. But the reference that i found on forum or conference paper just explain how joule thief circuit works, not the ...
28 views

### Can I use a 555 PWM signal to control

I want to use a 555 PWM signal to control a motor. I also want represented the speed of the motor with an LED graph using a LM3914 led driver. Can I use a digital signal to control the LM3914 ...
158 views

### Difference Between RMS noise and PSRR in an LDO

I am trying to choose a low dropout linear regulator to partially smooth the output of a dual rail SMPS I'm using to power analog circuits. I'm confused about the difference between the specified RMS ...
38 views

### What is the corresponding MIPS code?

Assume that variables f, g, h, i and j are assigned to registers $s0,$s1, $s2,$s3 and $s4, respectively. Also, assume that the base address of the arrays A and B are in registers$s6 and \$s7. ...
31 views

### Splitting a power supply to two monitors

I'm working on a project that requires 2 (identical) LED monitors, each of which has a separate power supply that outputs 19V 1.3A. To save space, I would like to instead use a single power supply ...
11 views

### Ratio between RFID reader and tag antennas

If a tag's antenna (45mm x 75mm) is larger than the reader's antenna (20mm x 26mm), could this pose coupling problems when trying to read the tag? The reader functions correctly with tags similar to ...
27 views

### On-board st-link programmer on F411 Discovery board cannot connect

Backstory: I have STM32F411E-DISCO board which has on-board st-link which i used before without problems (also programming external stm's). Today i tried to program STM32F103C8T6 with SWD connector (...
40 views

### Ideal 24V DC to DC 5V Converter just to feed 556 IC

I'm trying to find a best match for a regulator that can feed dual timer ic. The 5V circuit is dedicated to that IC which will generate a PWM pulse signal to PWM control the FAN speed. It's a 4 pin ...
345 views

### N-Channel Mosfet as Switch

I have a few n-channel MOSFETs (the irlb8721's) and I was able to use it as a switch to control an led with the gate at 5 volts. I would like to change the source/drain voltage to 11.1v from 5v and ...
75 views

### Four Layer PCB doubt

I was looking a raspberry pi zero board, and I think it is four layer pcb, but I dont understand now why the designer used a ground plane on top and bottom layer? It is assumed the four layer pcb has ...
39 views

### Adequate Power Supply for 300 Daisy-Chained LEDs

I have 300 LEDs (ws2812b) wired in a series. They were sold as 150 LED/5 meters and rated to power at 9W/m, so 45W/5m strip. I would need 90 Watts to power my entire 300 LED strip. I have a 3-rail ...
38 views

### 4 bit Binary Divider Circuit

We are making this 4bit binary calculator project but sadly our divider circuit didnt worked. Can you give me some schematic for 4bit binary divider? Thank you.
52 views

### How to clean circuit damaged by bleach?

I was trying to remove stains on a fiber optic party tie using bleach, however it seems a small quantity has leaked inside the controller overnight, causing some corrosion and preventing it from ...
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### Is my assembly code in MIPS correct?

I've started studying assembly, and I'm trying to solve this problem: For the following C statement, what is the corresponding MIPS assembly code? Assume that the variables f, g, h, i, and j are ...
68 views

### Can someone explain this constant current load circuit?

I'm currently a rising junior in EE and I was just wondering if anyone could help explain this circuit for me. The purpose for this is because I need to learn how to build a discharger (constant ...