# All Questions

114,522 questions
38 views

There are 2 software tools provided by ST to flash their STM32 MCUs namely STM32CubeProg and STLINK Utility STM32CubeProg Page says: STM32CubeProgrammer (STM32CubeProg) is an all-in-one multi-OS ...
29 views

### Simple Animatronic - slow repeating/reciprocal motion for a window display

I am trying to rig a contraption to pull a model hot air balloon back and forth along a curved horizontal track. Its motion is both horizontal (6’) and vertical. I have built the track and rigged the ...
39 views

### 1 bit adder-subtractor circuit truth table

today in class my teacher mentioned the truth table for an adder-subtractor circuit was the same as that of a full adder... I have been trying to understand and wrap my head around this fact but I ...
37 views

### ST-LINK and PA13,14 Pins on STM32F407

If I use PA13,14 pins for flashing my MCU via ST-LINK programmer then can I also use these pins as GPIO in the same circuit? Will that not disturb the ST-Link if some analog or digital circuit is ...
44 views

### Why is shielding effectiveness different for various hole geometries?

I have run into the equation below in various literature/app notes. (example). I have never seen the derivation for such an equation and don't understand why round apertures are more effective at ...
64 views

### How do these diodes prevent opamp from saturation?

I cannot understand how the clamping diodes prevent opamp from saturation when the switch/FET is off in the following sample-and-hold circuit: I only know that if the negative feed back of an opamp ...
31 views

### ESP8266-01S OFF State (CH_PD at LOW) Draining too much current

I have this project in which the life of the battery is imperative, after various designs i came up with this one: As you can see the pushbutton labeled START puts the CH_PD pin on HIGH for a brief ...
32 views

### STM32F407 Selectable External or Internal Oscillator

I wonder if its possible to switch between external and internal oscillators at runtime? Can I do that configuration in CubeMX? The idea in to put a jumper on a GPIO pin to do the selection at runtime....
9 views

### HM-10 Bluetooth: How to read characteristic data via serial commands

I'm programming an Arduino to use an HM-10 BLE device in Central mode to read a BLE Peripheral. I'm able to discover and establish a connection with the Peripheral (via AT+CONnnnnnnnnnnnn command) ...
39 views

### LED-strip PWM works with Raspberry Pi, doesn't work with Attiny45

I'm trying to control an RGBW analog LED-strip by PWM modulation. When using an Attiny45 the LED-strip just blinks at a low frequency (approx. 2-3 hz). However, using a Raspberry Pi 3 to control PWM ...
26 views

### Simple Circuit: light source seperated from signal source?

Forgive me for the simple question! How would I create a circuit for a light that is switched on when another light is switched on? Basically I want to use a more powerful source for a new light ...
33 views

### Minimal circuit to flash STM32F4 using STLINK

I wonder if I need to put some circuit between STLINK and STM32F4 MCU to flash it or does it simply require to connect the wires 1:1 directly? I cannot find it in the datasheet.
33 views

### What is the 'right' way for a 3-Phase Watt Meter to determine import-export Watt-hours?

What is the correct way for a 3 Phase Watt-Hour meter to measure total import/export watt-hours? I ask because I have seen this done in 2 different ways both in 'approved' meters: Assume that: Red ...
50 views

### Can STM32F4 USART be used as UART?

There are 4/2 USART/UART ports in STM32F407 (Page 15) MCUs as shown in the image. I need 4 UART ports in an application. I wonder if its possible to use 2+2 (UASRT+UART) ports for my purpose in this ...
1k views

### Why isn't there any EEPROM in STM32F4 MCUs?

Why isn't there any EEPROM in the STM32F4 series MCUs? Mostly I have Microchip MCUs and they have EEPROM available in them, but I just found out that it is not available in the STM32F4 MCUs... And it ...
58 views

### Why doesn't the emitter resistance of a BJT depend on the AC current?

When designing BJT transistor amplifiers, one calculates the emitter resistance of BJT: $r_e=\frac{26mV}{I_c}$ where the voltage is the thermal voltage at room temperature and $I_c$ is the bias ...
79 views

### Logic circuit designs in industry

i wanted to ask what logic designs are used in industry for different logic functionalities? So for example XOR gate: The 1st image would probably save more space on a circuit, but for the second ...
47 views

### Constant Current Regulator position in a series circuit

I'm designing a circuit with 3 LEDs, a CCR (NSI50350), and a power supply in series. My question is: Does it matter where I place the CCR? Can I design my circuit this way: +V--LED1--LED2--CCR--LED3-...
18 views

### Problem with simulation of a n- mosfet in pspice

Im trying to make a simulation based an a DC sweep from this circuit But at the moment of simulation I receive this warning WARNING: [NET0093] No PSpiceTemplate for M4, ignoring And it does ...
63 views

### DC-DC converter inductor current DC component

How does the dc-dc converter (e.g. basic buck topology) ensure that for different load currents (considering CCM mode only), the DC component of the current through the inductor is auto-increased/...
23 views

### Timimg of 4060 counter-oscillator

I'm using a CD4060B counter/oscillator and need to know the internal timing of the RESET operation. TI's 4060B datasheet says minimum input reset pulse width is 30nsec at 10V, and the reset ...
36 views

### Hall sensor graph

Anyone can help me to interpret the Supply Voltage vs Temperature from this datasheet ? What does it mean ? Why the supply voltage modifies ?
31 views

### How to add a Linear and Logarithmic Potentiometer in Circuit Wizard

I'm new in this kind of thing and I'm using Circuit Wizard (Circuit Simulation Software). I was trying to simulate an overdrive pedal circuit (https://www.instructables.com/id/Overdrive-Pedal/) in ...
39 views

### Accessory With 3-Pin LED strip?

I have a ton (160ft) of addressable RGB LED strip that I'm using for a fairly large project. After unboxing them I realized they all use 3-pin connectors (data, ground, power) rather than the 4-pin ...
103 views

### Is high current in a speaker the same as high voltage?

I'd like to build my own Amplifier, and because I know that the current creates the magnetic field, I don't understand, how amplifying the voltage makes it louder. I mean with high voltage doesn't ...
49 views

### Frequency tracking PLL type

I'm unable to understand which PLL type (1 or 2) is better suited for frequency tracking and why? Can anyone explain how that additional integrator in type 2 will affect tracking? Thanks in advance!
44 views

### AC/DC power supply module with 20mA output current

i want get 20mA current with 24V ac to dc. I have found this power supply module with 6-9A output current but i need max 20mA. What can i add with this module to achieve my settings? I am powering ...
54 views

### Any Self-turning switch?

I am looking for a switch, which can turn between 3-4 stages and also do it by itself. Do you guys know what I should search for? Thanks :)
44 views

### AC motor design

Is it possible to have an AC motor with only a partial stator, one that does not fully encompass the rotor? Refer to the picture to understand what I mean. This would be needed to drive a spherical ...
23 views

I'm doing a project using OrCAD. I reopened the .opj file that I saved last time and didn't see the schematic I was working on last time. So I clicked on the page1 icon under schematic1 and capture ...
21 views

### Measure pulse width generated in one pulse mode using HAL

I need to generate pulse in one pulse mode and measure width of this pulse using HAL. I'm using STM32F446RE board. I managed to configure timer to generate pulse but I have no idea how to implement ...
50 views

### Why are project files in Altium modified every time they are opened? Is there a way to prevent this?

I use Altium Designer 18. When I open a project file (.PrjPCB), the asterisk ("*") appears next to the project name indicating that the project has been modified, but I haven't actually made any ...
43 views

### Real-time Image Processing [on hold]

I'm looking for hardware to manufacture a machine that will perform real-time image processing in the crop field, which hardware/machines I should use? Thanking in anticipation.
47 views

### Behaviour of Voltage on Base in a fixed BIAS Common Emitter Amplifier

I'm having some trouble understanding the behaviour of the basic common emitter fixed bias amplifier. I've been looking at this for awhile now and I'm starting to think there is a foundational ...
50 views

### What type of pressure or weight sensors are thin? (Arduino or R-Pi) [on hold]

I want to know if a person is in a walking path of approx. 10x1,5 meters. I thought on putting thin tables in the path and putting these sensors under each even table (to save some money): https://...
36 views

### assited gps vs differential gnss

i am writing as essay evaulating accuracy of smart phone gnsss for GIS data collection for part of the essay i thougt it appropriate to mention DGNSS and Assisted GNSS. So far i understand Assited ...
20 views

### What causes the fail-safe bit to be set in the SBUS protocol?

What causes the fail-safe bit to be set in the SBUS protocol? I know that the when the link between the transmitter and receiver is lost, the fail-safe bit is set, however, what constitutes a 'lost ...
65 views

### How can I dampen current spikes when using NPNs to drive an LED

Hi I have the following circuit, its purpose is to flash an LED once per second. I'm using a pair of transistors as a constant current source but I observe current spikes of 20% or so when it is ...
42 views

### Is it possible to make hierarchy of constants in System Verilog?

Is it possible to make a synthesizable hierarchy of constants in System Verilog? For example: There is a board with FPGA and several peripheral ICs. Each IC have some setting registers. Each ...
35 views

For a school assignment I have to make a counter, based on a 32-bit adder, that increments with 1 every clockcycle if 'enable = high' and 'reset = low'. When I try to use the adder in my counter ...
49 views

### How to choose the correct pc fan? [on hold]

I need to replace a pc-fan 2 pin(80X80X25mm). The only details it has are:12V/0.14A.(no RPM/CFM details). Will those details(voltage/current)enough and i can pick any 80X80X25mm 2-pin pc fan which has ...
46 views

### How do I calculate constant values across several modules at compile time in Verilog?

I have a Verilog module that uses three instances of the same low-level module, called 'pole'. The instances are identical, except for a constant offset value, which is provided by the top level. ...
5k views

### Why does RAM (any type) access time decrease so slowly?

This article shows that DDR4 SDRAM has approximately 8x more bandwidth DDR1 SDRAM. But the time from setting the column address to when the data is available has only decreased by 10% (13.5ns). A ...
86 views

### Noob question: blinking leds with pn2222A and 9v battery

I'm kind of new here. I've been roaming around the forum for a while trying to figure out how to finish up this circuit I'm building and really need some help. I'm trying to build a blinking LED ...
56 views

### Is it possible to upload an arduino sketch through the serial port (RX) instead of USB [migrated]

In another words, is it possible to develop a custom bootloader so sketches can be uploaded via serial connection made using the RX/TX pins and not via the USB connector (I am using Pro Micro boards)? ...
57 views

### How the frequency of oscillation is determined in a multi-resonance oscillator circuit?

If we have a self-oscillator with multiple resonant frequencies, what are the criteria for the preferred frequency of oscillation? For example, a push-pull oscillator with parallel-compensated two ...
67 views

### How to calculate current on diode [on hold]

How to calculate current on diode? I use silicon diode Um = 5V R1 = 43 Ohm R2 = 70 Ohm
2k views

### Why does the current not skip resistors R3 and R5 when R6 and R4 have no resistance?

I do not understand why the current still flows through resistors R3 and R5 when R6 and R4's resistance is 0. To me, it would seem that the current would skip R3 and R5, however the answer key says ...