# All Questions

114,522 questions
3 views

### Circuitry to measure sub-nano ampere current

Is there a well known methodology to design a IC circuitry to measure sub-nano ampere or even pico ampere currents within a very short delay of nano seconds? The SNR could be assumed to be fairly good ...
11 views

### What is wrong with this single supply opamp circuit for audio?

I am currently building an output stage for a DAC with opamps in single supply configuration. Here is my circuit from LTspice: I have exactly built this on PCB, so I am talking about the real thing ...
10 views

### N-Channel MOSFET: Gate keeps the source-drain open even when it gets a “LOW”

I’ve got an Arduino MKR1000 that I’m trying to connect to a 4-AA battery pack, a RFP30N06LE 30A 60V N-Channel Power Mosfet and a push button. My goal is to have the MCU program run once at each push ...
12 views

### Can I power Beagle Bone Black Wireless (BBBW) with 3.7V LiPo?

This helpful question pointed me into the right direction for powering the BBB with a 3.7V LiPo battery. However, as this answer demonstrated, I won't be able to give the WiFi/BT module power in doing ...
29 views

### Resistors parallel with motor?

A pcb we've been asked to look at has two 15k 1W resistors in parallel with a 15A AC motor. Silly as it sounds, we're a little stumped why they're there. It's probably bloomin' obvious, but we can't ...
21 views

### Wiring colour code/law on universal power supply

Is it legal to use brown and blue for live and neutral wires in equipment sold in the USA, which uses 110v? I was looking at a teardown of an ATX power supply and one of the photos (see below) showed ...
25 views

### What does “driven” or “driving” mean in terms of electronics?

It is a silly question to ask, but I keep seeing statements like "driven by the output signal" or "X drives the load". What does it mean to drive or be driven by X?
25 views

### Under which specific (formal) conditions can I apply the superposition theorem?

Superposition theorem fails when you have two ideal (identical) voltage sources in parallel. Under which specific constraints can I apply it? I have read that, in DC Circuits, superposition requires ...
30 views

### Xilinx Spartan 6 speed sabotage?

I'm trying to use Spartan 6 fpgas at the speeds they purport to support in their datasheets. However, when I try to make a bit file, I get a message saying my design is "not supported". It compiles ...
29 views

### Is the 2 to 1 MUX universal?

Is the 2 to 1 multiplexer universal? Can it create a 7 to 1 multiplexer by multiplying its logic circuit?
28 views

### How long should a socket be kept open [on hold]

When using TCP Sockets to periodically poll a server for data (Say a few times a sec), does it make sense to keep a socket open constantly, rather than creating one, and connecting each time you need ...
18 views

### RAM Row and Column Decoders

I keep seeing similar diagrams of RAM like this abstract picture of a simplified RAM Layout. So I just arbitrarily selected this picture but my question is about this layout in general. My ...
22 views

### Altium Designer: polygon pour on signal layer

I'm designing a board around 2 Texas Instruments TPS65988. In the datasheet a layout example is shown where "fins" are placed around pads to provide further thermal dissipation. A pour to create this ...
35 views

### How do I determine the impedance of Z in this circuit?

I have a circuit shown as follows: Impedance Z = r + L + C. Known values: V1: 5V RMS @ 4kHz. (0 degrees phase) V2: 500mV and has 20uS from V1. Phase shift (360)(f)(t) -> (360)(4000)(20uS) = 28.8 ...
25 views

### How can this be simplified using only NAND & NOR gates

How can this be simplified using only NAND & NOR gates F= not(A)BCD + A.not(B).not(D) + Anot(B).not(C) + A.not(c).not(D)
17 views

### Amperage auto cut on and off switch

I’m looking at setting up a 12v motor or a small ac motor on an inverter to run multiple wind turbine generators (2 or 3 3200 watt or five or six 350 watt) wired in series through a connector box with ...
55 views

### How does a cellular network deal with a duplicate SIM?

I was pointed here from WorldBuilding. Say I had a cellphone, let's call it cellphone A, and made a perfect copy of it - SIM card and all - and let's call this one cellphone B. If I were to call ...
85 views

### 32.768kHz crystal making audible noise

I am doing a project to record and log the voltages of an 8 cell lithium battery. The project is based on an STM32 microcontroller, and logging is done on an SD card. I have made the first version of ...
25 views

### 24VDC PLC with 12VDC inputs

I have a 24 VDC PLC. It is powered by a power supply that takes in 12 V and turns it into 24 V. This 12 V is coming from a car battery. The inputs for this PLC is 12 V. I have a separate 12 V system ...
31 views

### What causes guitar amp to crackle and pop when connecting a smartphone to it?

I shortened a TRS aux cable (by cutting/soldering/heat-shrinking both ends of the cable). When I connect my laptop to my guitar amp (Peavey Vypyr 2) using this cable, it sounds good. But when I ...
43 views

### Why use many-pole motor for high speed?

I found in this teardown analysis of the Nissan Leaf drive motor that it runs up to about 10,000 RPM but is an 8-pole motor. My understanding is that the inverter cost goes up with frequency. The Leaf ...
19 views

### mpx5010 drifting

I have a MPX5010 pressure sensor that outputs a voltage proportional to applied pressure. Output is connected to an amp-op with gain=4 so my output is around 1V when no pressure is applied. That ...
446 views

### Why are “square law” devices important?

In the literature, I often see the notion of square law devices. Why are these devices important, to the extent that they have their own characterization as square law device? In what context does ...
28 views

### Design 3/5 DEC using 3/8 [on hold]

Can someone help me design a 3/5 decoder using 3/8 decoders? I have no idea where to start and how is it possible to do so?
17 views

### 90 VDC motor driven with 3HP -2 cycle gen [on hold]

90 VDC motor driven with 3HP -2 cycle for gen I have the big dc inductor go I need to have it in line before pwm to produce a useable 120-110 volts and at input rpm it's output is -168 volts with ...
32 views

### Component choice - NRF52832 for general MCU tasks, including RSA encryption

I need a bluetooth LE module for an embedded device. All it needs to do, is ingest serial data (over UART), encrypt it using RSA, and transmit it over bluetooth. Is this component adequate in terms of ...
42 views

### Calculating H-Bridge without motor specifications

I am currently calculating elements for an H-Bridge for brushed dc motor and PWM speed control that operates on 6V and maximum current of 2A. However I want it to work with different 6V brushed DC ...
20 views

### Which spec should I look into if I want to understand the communication between root-complex and the network interface card?

I've been doing the job related to the PCIe RAID card for a long time. There are specs called AHCI or NVMe which allow host software to communicate with the storage devices. I'm wondering if there is ...
32 views

### Ow to calculate resistance to use along with NTC 103 thermistor to measure temperatures between 0-100 degrees celcius

I am a complete noob to temperature measurement. I initially tried to measure temperature using LM35 but i got negative values at room temperature and the values were fluctuating a lot. I want to try ...
73 views

### how does single supply op-amp work while its non-inverting input is connected to ground?

In HCNR200 Datasheet, the page 11, figure 13-A, there is a sample that confused me. In this sample, the Vin is applied to the inverting input and if the electric current passes through PD1, PD1 ...
26 views

### BJT amplifier design with input resistance, output resistance, and open-loop gain requirements

so currently i'm designing a BJT Amplifier with these requirements: Open-loop gain = 35 dB Input resistance = 600 Ohm Output resistance = 200 Ohm Another thing is the only BJTs I can use have hFE of ...
39 views

### Questions about grounding points for an analog signal transmission

I'm planning to implement the following circuit I have drawn. But because there is no SPICE for such components I couldn't verify or test any overall workings. From left to right I will first ...
98 views

### DC-DC Buck Converter Failure Mystery

I'm a software engineer, so please excuse my gross ignorance of this topic. We are trying to figure out why our DC-DC converters sometimes fail and stop outputting power after a month or so of runtime....
38 views

### How to look for a good quality 11mm rotary encoder?

The rotary encoder attached to the wheel of my dear logitech MX1000 started glitching a few weeks ago. I took it out, tried cleaning it the best I could but it was still bad. So I went shopping ...
28 views

### Help required regarding Cypress 4200 coding

I am a newbie when it comes to Cypress chips. I am developing a capsense keypad. I recently started with CY8kit049. I can code into the chip on board. How can I code other PSOC 4200 chips too using ...
83 views

### Connect LM311 pin 7 to input pin Arduino

I'm brand new to the world of electronics and not very talented, so have mercy. This circuit lights up a LED when an IR beam is broken: I was wondering if I could connect the input pin of an ...
104 views

### How to measure micro watts (uW) [duplicate]

In an extreme low power project (MCU+BLE SIP running on a CR2016 battery for year(s)) I would like to measure the power consumption under different environments/algorithms. What would be the correct ...
30 views

### Can we store hex data through UART into flash and RUN it from that particular location

I am trying to store my hex file in another sector of the flash memory i.e (0x00050000) I want to store a hex file at different sector of the flash and to change the execution point to that address ...
25 views

### Protection against ESD/EFT/Surges

One of my project architectures looks like this: GPIO / 595 output / 12 VDC wire lengths will not exceed 25 cm. I have faced MCU lockup issues due to EFT in the past and want to make sure this ...
39 views

### 3.3v led and 220v water pump

I have relay connected to raspberry pi that switches the water pump on and off. I would like to add a toggle switch before the relay with a led. When the switch is turned on the led lights up and then ...
17 views

### LED display control [on hold]

I want to control LED display of 256mm*256mm having pixel pitch of 4mm. Can anyone suggest me which microcontroller can be used for that? or even possible arduino board or STM board.. I am new to this ...
14 views

### Transmission line theory - calculating phasor voltage over open circuit

I was working through a transmission line problem and ran into some trouble. I'd like to calculate $\tilde{V(0)}$ the phasor voltage over the open circuit corresponding to $z=0$. I'd like to ...
21 views

### How to Send s.bus signal from an arduino

i cant seam to find much for what i want on google. Im building a custom control panel for one of our wireless cameras, i can control it via S.BUS. just wondering if there was a way i can send an s....
91 views

### What is the purpose of diode in parallel with the resistor divider in MOSFET gate driving circuit

I have built several 200W AC dimmers using Microchip 8-bit CPU and the illustrated back-to-back MOSFET circuit (without the D1 diode). I have seen on Internet schematics with the D1 diode in parallel ...
56 views

### How does this electrostatic generator operate?

I'm trying to understand how this piezoelectric static generator works. I've found this video and I would love for someone to explain to me the operation of this device, and maybe assist me with a ...
67 views

### Routing traces over traces in two layer pcb

I am kind of new to PCB Design. I have a few confusions on my board layout, in order to reduce EMI in routing. I am designing a two-layer PCB design I am aware that when you route traces over ...
41 views

### 20 kV 100 mA Voltage Current Sensor

like the title says, i need to measure 20 kV 100 mA line. For the voltage part i found this:http://www.koncar-mjt.hr/en/docs/koncarmjtEN/documents/61/1_0/Original.pdf and this:https://www.hivolt.de/...
67 views

### Treadmill causes nearby electronics glitch

I don't know if it is right place to ask, if not correct/guide me. I recently have built treadmill workstation, where I could walk and work (rather than just sitting). But as soon as I turn on ...