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H: Wien Bridge Oscillator using OpAmp(LM386) works in simulation, but doesn't work in Breadboard?
This is a simulation of the circuit in multisim. It is a Wien bridge oscillator circuit, tuned at 1844Hz. I am mostly interested in generating sound of that frequency. It seems to work here in simulation but when I conne... |
H: Connect the oscilloscope to equipment with a common neutral and ground
I watched a video. At 3 minutes, the situation is shown when neutral and ground are joining. Why can this be dangerous? If we are talking about an oscilloscope, the crocodile must already be connected to the earth and nothing threatens me. The w... |
H: Powering my 5 volt project with AA batteries
I am thinking about using 1 AA Battery with these battery holders and this boost converter to power my 5 Volt arduino project, My project will pull about 100mA. Is there any problem with doing this? I don't see any issue with using these together to power my project, but... |
H: Antenna Array - Hundreds of elements forming thousands of beams - How?
How would an antenna array of 100 elements be able to form 5000+ simultaneous beams?
Or do I have it wrong, there would only be a maximum 100 beams from the 100 elements at any one time and those 5000 potential beams are realized by hopping the... |
H: 10V voltage with raspberry and arduino
is there a simple way to connect the 5V pins of the Arduino and the raspberry pi in series to get 10V ?
Thanks
AI: No. The pins are already all connected in parallel, you can't change that. |
H: Strange measurements for Vrms in LTspice
For my experimental methods class (basically an intro to electronics) in university we had to simulate a circuit, which was nothing out of the ordinary, it just produces different sine waves of 2 volts peak to peak. However, what was interesting to me was the fact that, when... |
H: HX711 chip not working
I'm working on an electronic weight scale using MSP430 and I need your help:
I've written the code using Energia and I've used the HX711 module for testing and everything works just fine. The final project requires everything being on a single PCB, which means I had to give up using the HX71... |
H: How to control RMS output of an DC-AC inverter?
Is it possible to design an inverter, with 270V DC input and RMS output of 115V. I don’t want to use a chopper or a transformer. Is it possible to meet this requirement by using PWM only? Or chopper/trafo is a must for this case?
I am using SPWM and I have already app... |
H: Determine transfer function from circuit with different currents
Just started on the topic Circuit Analysis, and am supposed to find the transfer function of the following circuit:
So I know I am supposed to use KVL to solve this problem.
I can first transform the circuit to:
From the circuit, I can see that bec... |
H: How to do serial communication between 3.3V and 5V devices using THT components?
I know that there are many questions dealing with logic level conversion/shifting between 3.3V and 5V devices, but my goal is to do do this with standard breadboard parts, so either discrete parts or DIP/DIL packaged ICs.
The serial c... |
H: Is this input-output relation correct? Schmitt trigger
OK, operational amplifier will want to keep node A at GND level. It will try to set its output so that the condition (inverting input potential = non-inverting input potential) is satisfied all the time.
So, why isn't a 5V of input mapping to -10 V which will ... |
H: Deriving Wheatstone bridge equation
I have the following circuit:
Here I have obtained the equation of Ud = U * ((deltaR / R)/(4+2(deltaR/R))). But I'm stuck on the part on how to derive that formula.
Any help or guidance is appreciated. (mainly since my book don't have the answer to this question that is within i... |
H: How to interface with an H-bridge IC (L298N) using a single PWM pin
I would like to know if it's advisable to control an H-bridge IC (L298N) using a single PWM pin?
Let me explain: By driving ENB pin High and by feeding complementary PWM (achieved by using a simple NPN transistor inverter circuit to invert PWM sign... |
H: Resolving an issue with syntax in SystemVerilog
I am trying to build a 4:1 multiplexer using 2:1 multiplexers that I've built. I am getting a few errors whenever I try typing the command:
vsim mux4_test
Array connection type 'reg$[1:0]' is incompatible with 'wire[1:0]' for port (sel): can't mix packed and unpacked... |
H: How the thyristor in a sawtooth generator reach its holding current?
In a sawtooth generator(circuit below) , the capacitor charges then when the thyristor turns on due to the bias voltage of R2 and R3, capacitor discharges to the thyristor like a short. Then after discharging the capacitor, the thyristor turns off... |
H: Make 9v ups for router with TP4056 and MT3608
I am building 9v UPS for my wifi router using TP4056 lithium-ion charging module and MT3608 stepup converter. If USB power is available I want MT3608 to get power from USB (TP4056 Vin Pin) otherwise from battery (TP4056 Vout Pin). I don't have mosfet, So I am using diod... |
H: Proteus thermal exposed copper (opening) for the pcb layout
I am using Proteus 8.7 and I am so confused about how to make a power plane (copper pour) exposed .
I mean I want that area free from green mask so that It can make its use as thermal dissipation area. Which layer should I use to make this opening ? The la... |
H: Resettable fuse nominal
I've found a part which looks like this:
I found out that this is a fuse, but i can't find any information about nominal. I suppose that marking show allowed current, but what about multiplier?
AI: It's simply the same thing upside-down, as you can see in this datasheet (similar datasheet l... |
H: How to find a compatible upgrade for a phone camera
I have a set of Android video glasses which are based on the PRIXTON C18 phone. I'd like to upgrade the camera to a better one - specifically one that supports changing the shutter speed as the current one does not.
I've tried a couple of different cameras from Eb... |
H: 3.5mm jack signal splitter
I need a solution for listening to music from 2 headphones/earphones on a single mobile phone. Using a speaker could be an option buy my girlfriend wants it this way. Anyway, while looking for a solution, the only thing I could really find is DIY videos of people making a cable like this ... |
H: How is capacity calculated when adding a battery in parallel with a faded or damaged one?
I was intrigued by the answer and comments on this question about connecting a second battery in parallel to increase capacity. The original battery has obviously lost capacity and is nearing its end of life. The OP wanted to ... |
H: Why frequency of a DC signal is chosen as zero? If the period can be anything, isn't it same for frequency?
This is a page from Oppenheim.
We can assume a DC signal as a repetition of 10 strips per 10 seconds/10 strips per 5 seconds. Like that, if we choose different periods, we get different frequencies also. The... |
H: Control two different DPDT circuits with one DPDT switch
I have a HDMI switch (pictured below) and a USB 2.0 Switch both have dual inputs and a single output, with no external power input. Both from what I can see are switched via DPDT switch. What I want to achieve is have them both controlled by a single DPDT swi... |
H: Stop USB-C plug from holding/clipping
Apologies if this isn't the right StackExchange site to go to, seemed like the best option.
I 3D printed a phone cradle for myself that was built for use with right-angle USB connectors. My phone has a USB-C port and the cradle does its job, but with a minor annoyance: I have t... |
H: Use two 250V series cap in APFC instead of single 400V
I have a EVGA 500W PSU with an APFC which is causing spike noises, presumably from the APFC or main switching as they both run in sync controlled by the CM68000TX combo apfc switching PWM chip
Noise (about 700mV every 16uS) comes in when APFC turns on, even on ... |
H: What are common ways that modern processors handle data hazards with asynchronous registers
I'm trying to design a processor in VHDL. While the base instruction set is done, I'm having trouble building on top of it.
Specifically, I'm implementing control and status registers (CSRs), which allows the system to be co... |
H: Understanding this startup circuit
In the circuit below, how is Q1 turned on? When there's voltage in the bias winding, it turns Q2 On and subsequently turns Q1 off. Also, does the end of R4+R7 keep floating when Q1 is off? It should go to ground. I'd appreciate any help to better understand the startup circuit in ... |
H: What is meant by the MOSFET is pinched-off?
What is meant by the MOSFET is pinched-off? It is same as in the JFET case where the depletion region becomes too large until the electron cannot flow through the transistor?
AI: When a positive gate-source voltage in NMOS is applied, As voltage increases once the voltage... |
H: Clarifications about GY-521 Module (Accelerometer and Gyroscope) for Arduino
I have some doubts about how to analyze data acquired through a gyroscope and accelerometer (GY 521, datasheet).
Precisely, let's consider this acquisition I have done when the module was still:
My questions are:
1) While I was reading th... |
H: Can you create a circularly polarized signal with dipoles that are perpendicular but not crossed?
All of the circularly polarized phased arrays that I can find use elements that are themselves circularly polarized, that is, two perpendicular dipoles that are crossed at their midpoints (the picture on the left). Wou... |
H: DALI Lighting (IEC62386-209) and Command-In-Between
Good Afternoon,
I'm having some trouble understanding IEC62386-209 section 12.7.3, which involves sending an "ENABLE DEVICE TYPE 8" command to DALI Control Gear prior to sending an extended (DT8) command.
The paragraph in question for the associated test sequence:... |
H: Why can't I short circuit a virtual ground with ground in OP Amps?
Consider this circuit for instance.
simulate this circuit – Schematic created using CircuitLab
If I calculate the closed loop gain of this circuit using Kirchhoff's law it turns out to be
$${V_o\over V_i} = {-R_2 \over R_1}\left( \frac{R_4}{R_3} + ... |
H: 1117 Regulator outputting 4.2v
I have an esp-12 soldered on this breadboard adapter. I mounted a 1117 3.3V (not adjustable ones) regulator to the board and removed the 0 Ohm jumper resistor as instructed by the manufacturer.
Using a regulated 5V power supply, I powered it up but I noticed it is getting hot. I measu... |
H: Chebyshev filter - theoretical vs simulation gain
Question is about the gain peak (or maybe more suitable would be growth) ocurring in higher frequencies (>20kHz) in Chebyshev filter 4-th order in simulation (simulated using Bode Analyzer in NI Multisim) - what's the reason for this? Theory shows that gain is going... |
H: Audio amplifier design problem
I am trying to design an audio amplifier circuit using BJT
These are the requirements of the circuit
Input signal: 50-100 mV (It's the output of my iphone's mic)
2W-4ohm speaker
There is no requirement for DC voltage source. I can choose so as to feed enough for my circuit.
Here's my... |
H: How to fully discharge supercapacitor?
My biggest problem is when I discharge a supercapacitor, let's say 100F 2.7V, I use a boost converter, but all boost converters have a minimum input voltage of about 0.9V. But the capacitor still has a lot of energy, about 40%.
It is frustrating because I'm not able to use thi... |
H: Holding torques of a 7W stepper and a 48W stepper
Does anyone know why a 2.5V 2.8A (=7W) stepper has a holding torque of 1Nm whilst a 24V 4A (=48W) stepper has a holding torque of only 2.7Nm:
Stepper 1:
Stepper 2:
The latter draws 7x the power, but gives just 2x the holding torque. The inductances are roughly the... |
H: Is this a capacitor in series with the power source?
I'm a complete newcomer here. I was looking at this small circuit and it looks like there is a capacitor connected in series with the power source. Is it possible that this is the case, or do capacitors always have to be connected in parallel with the power sourc... |
H: What is this spongy material?
Hi, while I am tring to repair electronic circuit. I'm encountering this sponge. I wonder what is this sponge? and can I find out what it is used for. I often see this in sensitive circuits like in laptop board and near to cooling parts. Adheres on cooler materials
AI: It is some kin... |
H: What is this called, PCB bevelled fingers?
I found this non-plated fingers PCB connector, with blackish color, in a Logitech MK240 wireless keyboard. This fingers connect between the PCB and plastic sheets wiring (for the keys).
It is a bit beveled, or I'd say furrowed (black has more bevel than grey in the pic), ... |
H: Different connections on positive and negative pins in PCB design
I've seen some designs they have connected pins of power components differently.
For example in a buck capacitor at the output of a DC to DC power supply I've seen the positive pin on direct connection and the negative pin on thermal relief connectio... |
H: How to code in assembly language for floating point exponentiation?
I have problem calculating raise a to the power of b (a^b) where b is a floating point number.
In my case, b=-1.45. So the expression is a^(-1.45).
I'm using PIC18F4520 microcontroller and I don't know how to implement it in assembly language or it... |
H: What about MCP23S17 GPIO pins output ports being also used to be read by input pins?
We are connecting Raspberry Pi3B with some MCP23S17 expanders:
MCP23S17.
I have read that they could emulate an open-drain outputs, playing with high Z state of the pin when configured as input. What kind of input and output those... |
H: Preventing Interference when using RF transmitters and receivers
I want to use a "listen-before-talk" approach to transmit data from sensors connected to a transmitter and receiver pair to a MCU connected to a transmitter and receiver, which means that the sensor will only transmit data once it has been asked to do... |
H: Continuous light: do LEDs flicker like fluorescent lights?
Continuous light - do LEDs flicker like fluorescent lights?
Under fluorescent light there is a flicker.
As I understand LEDs work only with DC current, thus they have a AC to DC transformer circuit pumping electricity into them. That would mean that they em... |
H: Transmission line reflection. I would like a non-mathematical explanation
I am a licensed radio amateur, and find bewildering the many different explanations, which range from folksy urban myth to Maxwell-Heaviside Equations, of what happens at the termination of a transmission line or feeder. I realise that they a... |
H: Very accurate time measurement
I'm going to measure very short times as accurately as possible. The device will get first one pulse and within 150 microseconds six more, each on their own wires. The time between first signal and each of the six other signals must be measured as accurately as possible. The accuracy... |
H: Overclocking an AVR microcontroller by using an external oscillator with higher frequency than uC supports
What would happen if I would connect an external oscillator that has a higher frequency than the microcontroller (AVR) supports? Will it blow up, constantly reset, or what?
AI: This is generally called "overcl... |
H: Voice playback IC
I was looking for cost effective voice playback IC and came up to ISD 1700 series. Another brief datasheet is here. I don't believe with the same footprint and only for 3-4 bucks I can get up to 16 min voice playback(if I am wrong correct me). However I wasn't able to find how to program the chip ... |
H: CMOS Inverter Voltage Transfer Function
So let's say I have a perfectly symmetrical Voltage transfer function curve for my CMOS inverter. The curve looks like this:
The question is, how would this curve change if the size of the NMOS transistor was reduced.
My answer: The curve would still be symmetric but would ... |
H: 12VDC power supply question
I have a 12VDC 500mA power supply and I want to power two (2) separate items, by using a "Y" adaptor. The first item is supposed to use this exact power supply, but the second item tells me to use a 12VDC 250mA power supply. They are both a couple different projects with LEDs. I do not w... |
H: Spark Transmitter with flyback driver and good arcs
I recently built a Fly-back Driver with a fly-back transformer and a primary voltage input of 12 volts and the arcs are about an inch long ( i don't know the exact output voltage because I don't have the ability to measure it ). I have heard that in the 1900's the... |
H: Format Approach to NODAL ANALYSIS
SITUATION:
Nodal Analysis is nothing more than applying KCL and is very powerful. I'm working on developing a more clearer perspective of two approaches in Nodal Analysis "GENERAL & FORMAT". Mesh Analysis is also quite powerful but my questions below are pertaining to Nodal Analysi... |
H: What is typical power consumption of FPGA devices
I am new to this site and had one question. I know typical CPUs have power consumption (TDP) in range of 100-200W, for example Intel Core2. I wanted to know what is typical power consumption of FPGAs. I saw this paper, where it says power consumption of Xilinx xc5vl... |
H: PCB footprint of Xilinx Kintex 7 FPGA
I am laying out a board with a Xilinx Kintex 7 FPGA (serial number XC7K70TFBG676). The first step is to create a footprint of the FPGA for my layout tool, the Cadence Allegro PCB Editor.
Does Xilinx provide Allegro footprints of their FPGAs for easy import?
AI: It is not even n... |
H: Am I following the procedure to set the sensitivity in Try Mode for the A1362 Hall-Effect sensor correctly?
I am following Figure 5 pg. 18 of this data sheet: Vp(HIGH), Vp(MID), Vp(HIGH), followed by 0-255 Vp(MID) pulses that increase the sensitivity each time Vp(MID) is applied.
However, when I bring the north ... |
H: What does "P. C. MOUNTING" stand for?
In this datasheet, last page, what does "P. C. MOUNTING" mean in the diagrams?
AI: Printed Circuit mounting. This part of the drawing shows the recommended pad size, hole size and spacing on the PCB. Copy this when you create a "footprint" for the switch in your PCB layout syst... |
H: BJT Pre-Regulator
I have a circuit that has an input of 35V peak and I would like to drop the voltage down to 5V 200mA. I was recommend to use a pre-regulator in the following configuration:
The good thing is that it works. My question is what is this BJT/preregulator doing? How does it work?
AI: The base voltage ... |
H: Set Kd too high
In a control system, why when I set Kd (differentiate) too high then it has a buzzling sound? Is it because of the system is moving up and down very fast?
AI: Some sort of vibration is common when the D term gain is too high. This is because it amplifies whatever noise is on the error signal. If t... |
H: Is an ADC always necessary between 8051 and zero crossing detector?
I am making a SCR(Thyristor) trigger by using 8051 microcontroller.
I have a here is a zero cross detecting (ZCD) circuit which detects the zero points and this is conveyed to the 8051 which will do further action.
The ZCD circuit is made up of BJT... |
H: What's the use of a decoupling capacitor near a reservoir capacitor?
I've seen some circuits where a decoupling capacitor is used as well as a reservoir capacitor, like this (C4 and C5):
I've read about decoupling capacitors and for me it looks as if they are meant to remove small fluctuations in the supply voltag... |
H: What is a one-bit ADC good for?
I have recently heard of the concept of a one-bit ADC, and have seen it implemented in the context of a sort of digital-to-analog converter (oddly enough), and I'm wondering, what is the point? Why not simply use a higher-resolution ADC, if higher resolution is desired?
AI: To give a... |
H: Multiplexing an 8x8 Matrix - Why Transistors?
I'm trying to understand how to properly multiplex an 8x8 matrix (or any large amount of LEDs)
http://arduino.cc/en/Tutorial/RowColumnScanning
However, I'm getting a bit confused, since I've found others like this: http://garagelab.com/profiles/blogs/arduino-scrolling-t... |
H: Options for getting 3.3v @ 220mA from small batteries
I have a system running at 3.3v requiring 70mA at most times and 220mA at peaks (roughly 20% of the time). I'd like to find a way to power this from coin cell batteries or other small portable source. Battery life needs to be about 1h but size should be as small... |
H: What is the purpose of R2 in this discrete voltage regulator circuit?
I understand the general working of the circuit - R1 biases Q1, Q2 acts as an error amplifier closing Q1 just enough to get 1.4V at it's base. What is the puropse of R2?
simulate this circuit – Schematic created using CircuitLab
AI: R2 simply m... |
H: Where to find buttons eagle cad
Does any one know where to find buttons in EAGLE that look something like the one in this schematic?
I'm making a schematic and all I can find are complex looking buttons. If those are not available, then can someone help me find a normal switch, like this:
I can't seem to find th... |
H: Information about time-to-digital converters (TDCs)
I'm going to measure short times (max 150 microseconds). To do this I will use time-to-digital converters (TDCs). They don't seem to be very common and it's hard to find information about them on internet. I wonder if someone here can answer my questions.
Which c... |
H: Random-delay gen
Some years ago I tried to design a circuit where (among other things) a LED flashes after a kinda random delay. As it didn't work, (and after raging and destroying everything that could help me solve the problem) I am wondering if there was a fundamental mistake or I was just too sloppy.
Today, I f... |
H: VHDL: Architecture naming and interpretation
Note: I am using Xilinx's ISE and have an FPGA board to work with (with switches and lights and so on), and I've hacked together some simple projects so far. At the same time I'm reading several tutorials to build a foundation for what I'm doing.
I've seen various entiti... |
H: i2c on different logic level devices
I'm having a problem making LPC2148 work with SRF10 sensor. LPC is 3.3v device with 5v compatible i2c (at least user docu claims that). On the other side there is SRF10 device which is 5v.
I have tried with both levels as pull-up lvl connected with 4.7k resistor (i have 3 device... |
H: How can I detect a pulse from a device with the AC'97 component of a Xilinx Atlys board?
I have a digital device which transmits rapid pulses over a 3.5mm audio cable, indicating that some event has occurred. I want to connect that device to my 3.5mm line in jack on my Atlys board and determine how many of those pu... |
H: Mathematical approch to measuring current, voltage and resistance of mixed series and parallel
If there is a circuit like the one below, where all resistors are 1k ohm, how does one determine the currents? The voltage sources are all 10 volts.
The problem I am having is that I do not know if the top voltage source ... |
H: What is with the popularity of the 8051 Core?
I keep seeing the old 8051 architecture around a lot. But I can't see why people would want to use this old architecture in their products when there seem better alternatives around, such as ARM cores, and if you're not designing your own MSP430s, AVRs, PICs offer a goo... |
H: Eco-roof flow meter with "counter channel" output - what is that?
Some background:
I'm working on an eco-roof flow monitoring project and we want to hook up a Unidata 6506G tipping bucket flow gauge (our effluent flow is in a strange low range range where we needed a large tipping bucket) to a Steven's data logger.... |
H: How to force Keil to compile with software float for STM32?
When I am trying to create a float variable in Keil to program STM32 it just crashes.
I had a look online and as far as I read it tries to use hardware floating point unit (which is not enabled and I don't want to use it).
If I want to use software based f... |
H: Question about the Inrush Current in LDO
I have a doubt with inrush current limiting for an LDO. To understand that, I referred old literature of capacitors and others. I have some conflicting arguments which I need to clear out:
This is from Wikipedia:
The current into a capacitor is known to be
: the peak... |
H: Raspberry Pi and Touch / Pressure Sensor
I have to create simple device for a promotion campaign. I should react when someone seats on the chair, so I need advice on choosing the right sensor. Should it be pressure sensor and what kind is better for Raspberry Pi?
AI: If you just need to detect someone sitting on a ... |
H: Microcontrollers with Floating Point Hardware
I know this is a "contemporary" question, but I think it's a useful one to aggregate some knowledge. What are some currently available microcontrollers that sport a hardware floating point unit (i.e. that aren't going to cost me a huge RAM footprint to do floating point... |
H: How to avoid/reduce heat for three 1W LED's?
I'm asking on behalf of a colleague who wanted to make solar powered lighting for poor people.
Electricity generated by solar cells are stored in a car-battery sized 12V battery, and that current is passed to three 1W LED's which operate at 3.3V. She's tried connecting i... |
H: What's the equivalent zener voltage of two parallel zeners?
Assume we have two zeners connected in parallel, one with a zener voltage of x volts, and one with a zener voltage of y volts. What will be the equivalent zener voltage of the circuit?
AI: The one that has the smaller voltage. It will hog the current unti... |
H: Suitable components for logic control
Having never worked with electrical components, ignorance of the most elementary sort is holding me back. I'm looking for suitable components for logic control of DIY home automation equipment. I've looked extensively online and have no idea. What websites, books, etc. can I... |
H: EMVA standard 1288 SNR formula (equation 11)
I'm trying to understand equation 11 for Signal-to-Noise Ratio in EMVA standard 1288 Release Candidate 3.1:
http://www.emva.org/cms/upload/Standards/Stadard_1288/EMVA1288-3.1rc.pdf page 7.
Using equations 6 and 8 I arrive at something similar to eq 11. However for me th... |
H: Wall supply transition to a 2nd wall supply
A device has various supply rails, but they are all derived from one 9V wall supply via switcher and linears. What kind of issues can occur if the device is unplugged from one wall supply and then plugged in another, within seconds?
Are the grounds of the two equivalent ... |
H: Connection of EZ430-RF2500 development tool with PIC18f877
I want to conect the ez430-rf2500 development tool with PIC16f877 throught uart, do I have to use a max232 chip in order to be able to communicate between those two MCUs or it can be done without it.
AI: You can connect the PIC's UART to the MSP430's UART d... |
H: PackageReference in Altium Designer
In Altium Designer standard libraries, parameters PackageReference and PackageDescription are same as Footprint Name and Footprint Description.
I'm also going to have those fields in my new components, I wonder if the above is plain copy or those fields are referencing to each o... |
H: Arduino GPS Camera
I am working on a project through my school. We are going to be shooting cameras on spikes into the ground beside grid roads for tornado tracking. The spikes will be equipped with two cameras. My job is to design a system to track the spikes. I need to get GPS location and send it to a computer i... |
H: Can this circuit be a Schmitt trigger?
I'm just learning about Schmitt triggers with op amps. I have the circuit below, and I tried to go through the calculations to find the high and low thresholds. What I'm understanding from my calculations is that the high voltage threshold and low voltage threshold are the sam... |
H: Seven segment display becomes dimmer as more segments are lit
I've got a common cathode, two digit seven segment display (LDD-N512RI-RA) hooked up to the GPIO pins of a microcontroller (Coldfire MCF52233 DEMO). The problem is that the brightness of the display varies with the number of segments lit. As more segment... |
H: How many functions can I put into an arduino uno?
Is it realistic to put the following: GPS module, GSM module, SD card slot and about 4 analog sensors into Arduino uno? (have not yet goten an Arduino in my hands).
AI: How many functions? That depends on a few factors. First, will I have enough pins? The GPS module... |
H: GPIO input connected to garage door button
I know there are other GPIO / Garage door related questions, but this is not a duplicate- I need to read the status of the garage door button, not a garage door sensor.
I would like to connect the garage door's button to a GPIO input on my Pi. I want to be able to trigger ... |
H: Schematic symbol confusion
I'm looking at building an audio amplifier using the following the TDA7385 amplifier IC.
Here is the data sheet: http://www.mouser.com/ds/2/389/CD00002618-109852.pdf
I am confused by the application circuit which is documented in the above datasheet, specifically where it does not mention... |
H: Do you recognise this signal?
The story for this signal is the following. I've bought an NAD C 356BEE amplifier with an integrated MDC DAC module. It has optical and USB input. The optical is OK, but if I connect the DAC to my PC with USB, then it makes clicking/popping noise at specified times. The click frequenc... |
H: Is a low load resistor a big problem in low pass filter and amplifier circuit
I am going to use AVR's PWM output signal to pass through a low pass filter (maybe plus an amplifier). I found the speaker has a quite low resistance (8 ohms). I tried to simulate my schematic on Orcad, obtaining very a low voltage signal... |
H: How can I tell the size of a barrel power connector?
Spring cleaning, and I'm trying to get power supplies for all my devices with missing power supplies. They're all the typical barrel power connector, and I'm having a dickens of a time trying to figure out the pin/hole diameter.
I ordered the power supplies I n... |
H: What easily acquirable material changes its resistance when heated?
I'm trying to build a Resistance Thermometer that varies current/voltage output when heated. It has to be DYI, I don't want to buy anything done, only something like a light bulb, and this has to be easily changed, as the ideal temperature range I... |
H: Eagle 6 : Problem Importing Custom Parts
Recently started working on a new PCB board for a dev kit. I ran in an issue where I had made a custom part for the M50-3501042 2x10 male header with 0.05'' (1.27mm) pitch.
Note also that this is a through-hole component.
The issue I had was that I set the diameter of each o... |
H: Piezoelectric Sensor and the ADC
I would like to hook up a piezoelectric sensor to my ATmega8 microcontroller via its ADC.
The reason being is that I would like to use the sensor as a force sensor. I noticed that the harder I press it, the higher a voltage it delivers (but for a very short time). This is expected b... |
H: Negative and positive voltage from a single 12 V battery
I am trying to power my CPU with a single 12 V battery.
For 12 V, 5 V, and 3.3 V I have decided to use a buck converter using a 555, but I can't find any solution to get -5 V and -12 V out of that same battery.
I have tried using a 7905 for -5 V, but it's hea... |
H: Portable 5V power supply
I am usually in need of powering my microcontroller projects with 5V. Typically this is not a problem, as I use any power supply (converted PC power supply, wall adapter, USB, etc.).
However, when I need my projects to be portable and lightweight, I am not quite sure what the cheapest/easie... |
H: Could a lamp plugged into an outlet be dimmed using a variable resistor?
If you had a variable resistor connected between a lamp and the wall, could it be dimmed with a variable resistor?
Would it be practical, i.e. would it waste much energy? And would it affect both current and voltage or only one?
AI: Yes; this ... |
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