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H: 5v to 12 Power Supply
I have really no idea about electronics.
I am trying to provide IR lighting for my night camera that I use with the raspberry Pi.
The Pi is powered by a 5v usb power bank. The IR requires 12v.
I purchased these:
https://uk.banggood.com/DC-12V-48LED-IR-940nm-Night-Vision-Infrared-Illuminator-Bo... |
H: Power supply problem, what is the correct solution?
My result is "No" because the DC voltage is around 14.86 v and the ripple voltage is around 9.9 volts but I'm not convinced about the result especially for the ripple voltage. Does anybody get the same result?
Here are my calculations
$$V_{peak} = 15 * 1.414 - 1.... |
H: Locally create 3V3 from 5V for small load and uP GPIO
I am designing a 5V board and i need to read two outputs from the lithium charger using the 3V3-only uP GPIO, while also using them the same output pins to drive user LEDs; charger outputs are either GND or Hi-Z.
While trying to come up with a solution that tick... |
H: Please help me identify this connector type
Can anyone help me identify this connector types? I have tried finding this connector online and the closest one seems to be tamiya connector. But the ones I found being sold online has different locking mechanism.
This is the female counter parts:
It's used for a wash... |
H: Why use a tantalum instead of a ceramic capacitor?
On page 72 of the AD7124-4 datasheet it says:
Decouple AVDD with a 1 μF tantalum capacitor in parallel with a 0.1 μF capacitor to AVSS on each pin.
Why would this capacitor be specified to be a tantalum?
At this low capacitance a ceramic MLCC is cheaper and has s... |
H: How many amps between batteries that are wired in parallel?
How many amps will flow through the cables between my batteries if I have 2 batteries wired in parallel?
Let's look at a simple example:
We've got 2 batteries in parallel, and one 12v lamp that requires 3 amps. The wire from the battery to the lamp will r... |
H: What's a pigtail with regards to antennas?
Can somebody explain to me what a pigtail is with regards to antennas? I bought a 434 MHz rod antenna with an SMA plug and what I got was the antenna as expected and another short piece of wire with another SMA plug (female plug type):
Is the picture above a pigtail? What... |
H: How do I test a lawn mower magneto?
I'm trying to test the magneto from my riding mower. I followed some YouTube videos and tested it with a multimeter putting one probe where the spark plug would go and touching the other to the metal plates. I get a resistance of about 5.84 kilo-ohms. But I don't know what tha... |
H: What are the values of these 2 resistors?
What are the values of the two highlighted resistors?
Considering the brown band as tolerance and ignoring the first (black) band, I came to the conclusion that the values are 680 and 220 milliohms. Is that correct? Thanks.
AI: 0.68\$\Omega\$ +/-1% and 0.22\$\Omega\$ +/-1... |
H: How do I calculate how long it will take for a capacitor to discharge when shorted?
If I know the capacitance, series resistance, and the voltage it is charged to. I tried using a graph y=x/0.003
Where y is current and x is voltage, but now i'm lost, because I don't know where to put the capacitance. And then I wou... |
H: Probing With Multimeter Breaks LED - Happened Twice
Qucik background info:
I am using a 117 Fluke, brand new bought in 2020 from Amazon.
What happened/happens:
This is a very simple circuit, but for some reason the resistor keeps heating when I try to use red LED's which are rated at 0.007 Amperes, so I tried to c... |
H: I removed a little motor from my laptop fan and it won't run using a 9V battery
I realize this is may be a noob question so please point me to the right place to ask it if this isn't so. Anyway, I'm trying to build a little magnetic blender using a spare laptop fan. I tried plugging the red and black wires (and eve... |
H: Simplifying boolean equations with K-map
My professor told me that I could arrive at the simplified solution using the K-map, which I guess I did, however it does not seem correct.
The equation and corresponding solution are shown in the pictures below.
My simplification steps were:
ABCD' + A(B' + C' + D') + (A'B'... |
H: How to avoid negative voltage on MCU pin from RCV420 converter?
I am working on a circuit to convert 4-20 mA signal to 0-5 V to finnaly read with an analog input of an MCU (PIC16F886). The IC I'm using to convert the signal is the RCV420K which works fine. On the documentation of the IC it says that it needs to hav... |
H: Diode identification - zener?
I’m trying to replace what I believe to be a glass zener diode which I determined was overloaded in an electronic automobile delay module. Cathode was attached to a PCB (labeled “Z1”) and the anode was soldered directly to one of five “blades" which extends through the module and to th... |
H: How to find the right battery for my project
I am working on a project that requires 12v 12A of power. But I can't find the right battery. I have been looking at a few online tutorials about choosing batteries but they have not been very helpful.
The battery I am requiring is 12v 12A DC. and it needs to be recharge... |
H: Lattice XP2 -- Different voltages for different IO banks?
As the subject indicates: can I use different voltages for the different IO banks? (1.8V for some, 3.3V for some others)
Neither the datasheet nor the hardware checklist technical note explicitly say, AFAICS.
AI: The key document is one you didn't link to... |
H: Power saving circuit in pneumatic valve
I am looking for a pneumatic valve and I refereed a catalog. It has a power saving circuit in the valve and there is a circuit diagram and description of that.
I couldn't understand how this power saving circuit works. Below is the description about that as the catalog.
Can ... |
H: What is the AUX_IN and CD_IN connection on old Soundblaster sound cards?
What is the AUX_IN and CD_IN 4-pin connection on old Soundblaster sound cards? The card's model is CT4170. Here is an example
I think its some sort of input. Is there any schematic which tells me which pin is what? There was also a connector ... |
H: How to use chip XL6007E1 to build a boost ciruit?
My ciruit:
Input: 3.7V
But no matter how I adjust the potentiometer, the voltage did not rise.
How can I solve it?
AI: Look here: -
The most obvious problem is that the enable pin (EN) is floating. Try connecting it to Vin as per the data sheet: -
Other potential... |
H: Powering opamp from unregulated DC-DC Converter?
When using one of those unregulated, isolated DC-DC bricks (its output voltage can be as much as a few volts higher than its rating and varies with load) to power an opamp is a voltage regulator a good idea even if the opamp can handle the higher voltage? What would ... |
H: On/off switches board pinout labels
I would like to know if there is a pattern to name switches board pinout, at least, for these boards.
The boards are parts of a piano toy. First one for some effects buttons and second one is the piano keyboard.
The pins are named as P10, P11,P12, P13, P20, P22, P23, P40, P43 for... |
H: Switching Relay at Zero_Cross Point
I'm controlling 4 Relays(10A) with a controller. While randomly switching it without zero-cross my controller gets restart. To avoid this I'm switching relays at the zero-cross point, But my question is every relay had the different operating time(on time) and different release t... |
H: What was used as paint on insulation/conformal coating in the 1950s?
I'm restoring a multimeter from the 1950s and I was wondering what was used as paint-on insulation/conformal coating. It's the yellow/brownish stuff smeared on the screws and leads in the photo.
I suspect it is shellac, was this commonly used in t... |
H: Collector current in a BJT transistor whose base and emitter are forward biased
I'm reading a book about electronics and I have a doubt about a NAND gate implemented with Transistor-Transistor Logic. The question I have is actually about BJT transistors specifically (not the gate itself). I thought I understood how... |
H: Floating traces on MCU dev boards bad for noise?
When you have development boards for microprocessors with every GPIO pinned out on headers around the edge of the board, is the board more susceptible to picking up noise than a board without all those unconnected lines?
For example say you were using the ADC on the ... |
H: DC offset before signal being fed into an instrumentation amplifier from a bio potential source
I am trying to design an instrumentation amplifier, having 2 bio-potential sources as its differential inputs, each having peaks in the order of 10's of uV and a frequency band of 3-50 Hz. One of the main characteristics... |
H: What is the practical probability of a bit getting flipped during transmission?
We know that Coding Theory depends on the fact that the probability p of a bit flip must be less than 0.5. From Fundamentals of Error-Correcting Codes (pg.39), it states
In most practical situations p is very small.
Using the technolo... |
H: Is voltage reduced when load increases?
Would the voltage of a power source decrease if multiple loads / more load is added to it?
I am researching battery types, and wanted to know, if I added enough load to a battery how much / would there be any voltage drop?
Example: I have a 12 V set of batteries in series. Th... |
H: Why can't a single-supply comparator handle negative inputs?
I tried simulating a basic comparator configuration in Proteus with only a single supply. The reference/trip-point is 2V. However when I simulated the DC transfer curve, all negative input voltages are saturated to +VCC and not to the lower rail voltage (... |
H: Bypass cap on reference voltage?
For a voltage reference providing a reference to multiple devices, ADC, DAC, instrumentation amp... would there be some benefit in placing bypass caps right at the reference input to these devices even though they have high input impedance?
AI: Modern ADCs use charge_balancing or ch... |
H: Transformer Measurement and Simulation
I have a 220VAC:1200VAC 800VA 60Hz toroidal voltage transformer and I'd like to measure its parameters to simulate a circuit I'm gonna build with it, in order to understand better the transients. The measurements doesn't need to be very accurate. I have a very limited knowledg... |
H: How do these Zener diodes limit the maximum voltage seen by other circuit components?
This schematic is given in Texas Instrument's AN-1533 Application Note (Over Voltage Protection Circuit for Automotive Load Dump)
On page 4, the author says that the D3 Zener prevents the cathode of D1 from exceeding its maximum... |
H: Input filter on DC-DC converter when it is the only load on a source?
Many app notes recommend placing an LC filter on the input of a buck converter to stop switching noise travelling back and thereby affecting other parts of the circuitry. But in the scenario where everything in the circuit is powered off the buck... |
H: Damping to reduce error signals
So ive been doing some research on how overshoot can be reduced in an AC servo position system. I found out that tacho generators are used connected from the load to the motor that drives this load. However I found out that it may cause velocity lag and error. I found out this can be... |
H: Building primitive FGMOSFET for educational purposes
To illustrate how flash memory works, I thought to build a primitive FGMOSFET and show that it stores a single bit of information (charged, uncharged).
It would require a high voltage to charge, it could be unreliable and leak current, but it would show the basic... |
H: 1-2 second home power loss: some circuits stay powered - computer doesn't turn off. How is this possible?
We've been having some local power outages which last for about 1-2 seconds and maybe at times are only 500ms.
I've noticed that we have two computers which stay powered and I'm trying to figure out why.
The fi... |
H: Validity of superposition when summing powers from each harmonic
In Boylestad's Introductory Circuit Analysis 13th edition page 1176, there's an example about working out the total power dissipated by a circuit fed a nonsinusoidal signal. The signal is decomposed into:
DC component: 63.6 V
Fundamental: 70.71 V RMS... |
H: Nichrome powder acting as a resistor
I’ve been doing some experiments recently with metal powders and I’m wondering if someone can help me interpret the results and give me some advice.
I wanted to test how the metal powder would work in a circuit. I tested some graphite powder and some nichrome powder.
I made a ci... |
H: Some basic questions about an accelerometer's unexpected behavior while tilted
I have an ADXL335 accelerometer connected to my Arduino. Here is some code that I am running based off a tutorial:
xaccl[a] = float(analogRead(xpin) - 345);
yaccl[a] = float(analogRead(ypin) - 346);
zaccl[a] = float(analogRe... |
H: Which cable connection will result in a greater loss of power?
I know that running a power cable (the cable is carrying 5V DC, I plug in an AC to DC converter to the mains) that is, for example, 50m will cause losses in the power output. So if you measure at the source it will be 5V but when you measure at the end ... |
H: SRAM/DRAM Price Difference
An SRAM cell uses 6 CMOS transistors to store 1 bit of information. A DRAM cell uses 1 transistor and 1 capacitor to store a bit. So one could guess that for the same amount of information (say, 1GB), SRAM would be around 6 times more expensive than DRAM (if capacitors were free). In the ... |
H: Unknown indicator of package specification
I am creating the footprint of an IC, and the manufacturer has specified this below:
I cannot figure out what C0.3 stands for. Is it the length of the diagonal? If it helps, according to another drawing for this rectangular pad, X=1.55mm and Y=1.40mm
AI: C stands for cham... |
H: What is the meaning of this schematic symbol (labelled COMP.J1 JPAD3)
I am trying understand the schematic for a Waveshare Core 407I board, with an STM32F407IGT6 MCu. What is the meaning of this schematic symbol (labelled COMP.J1 JPAD3)?
Link to full schematic: https://www.waveshare.com/w/upload/4/4a/XCore407I-Sche... |
H: Adjusting Potentiometer Range
I'm using two 1K potentiometers and I want to achieve this result:
When the first pot is set to 1K (100%), adjusting the second pot should change the output from 0 to 1Kohms.
When the first pot is set to 500 ohms (50%), adjusting the second pot should change the output from 0 to 500ohm... |
H: Need help with reading mosfet datasheet (safe operating area graph)
What does indicated time in below graph means?
datasheet
AI: What does indicated time in below graph means?
It's the length of time that the MOSFET can reliably conduct for the applied drain-source voltage and drain current. For instance, with a d... |
H: How do you split a summing point into two?
I am solving a control system example on block reduction rules and stuck on this particular step. According to me, I can move the summing point ahead of the middle block to get G4 multiplied to both but that would not get the summing points in the form that they are in the... |
H: Controlling Z axis placement
What techniques are there for placing the components on a PCB at a desired height? e.g. so that potentiometers and switches can be both panel mounted and board mounted?
For example, are there adapter components designed to lift other components away from the plane of the board?
Reading ... |
H: Position components in KiCad for a test rig
I'm designing a test rig for a product. There's a number of test pads and a power connector on the PCB, which I want to match up with a tester device, i.e. the tester PCB should have pogo pins and the mating power connector in matching places.
The question: given the PCB ... |
H: Is this analog switch good for UART lines?
Currently designing a circuit to switch between two UART lines using an analog dpdt switch. Been searching for a while and found the BL1532. The datasheet says it's a DPDT USB2.0 Analog Switch, but not sure if this chip will work for UART since USB is pretty fast (not an e... |
H: Can you dim already dimmed LED lights
Ive installed LED downlights in my room, these :
https://www.screwfix.com/p/lap-fixed-led-downlight-contractor-pack-white-370lm-5w-220-240v-10-pack/728fj
they are controller via a smart dimmer switch, this :
https://www.amazon.co.uk/gp/product/B07BKXMS6C/
they work fine, dim up... |
H: FTDI and ST LINK devices together to STM32
I have an STM32 board (blue pill) that I am programming with the Arduino IDE.
I couldn't program it using an FTDI adapter because I couldn't make the Arduino IDE communicate trough the USART for uploading codes, so I am using a ST LINK V2 to program the STM32.
On the other... |
H: Damaged OLED LCD voltage regulator replacement
I have a 128*32 OLED LCD that is used with an Arduino. I recently damaged the voltage regulator and was hoping to be able to repair the board by soldering off the damaged component and replacing it with a new component. What should I replace it with? The datasheet can ... |
H: Why does voltage drop across resistance contradict Ohm's law?
Very basic question here.
I have been learning a ton about Ohm's law, and I don’t seem to ever be able to completely understand it.
One of which I am getting particularly confused about is voltage drop and Ohm's law.
According to what I know about Ohm's ... |
H: Sourcing Transformer with Specific Turns Ratio
I am looking at a building an electronics project that calls for a transformer with a specific turns ratio '1:4:50', and am trying to source a component. I am working on the project from this tutorial: https://circuitdigest.com/electronic-circuits/diy-stun-gun-circuit
... |
H: Using audio isolation transformer to clean power to a Raspberry pi
I want to "clean up" the powersupply to a raspberry pi that I am using for audio recordings.
I am getting a lot of low frequency buzz, i.e. 60 to 2000 hz.
I am wondering if I can use an 1:1 audio transformer to reduce the interference from the PSU t... |
H: Is this signal reflection or a damaged transmitter?
This is (an isolated, differential) capture, 1µs/div, of some Profibus communication over about 10m of cable. The first image is typical for about 90% of packets and seem fine. Most are +/-5v with slight deviation from device-to-device as they reply with data. T... |
H: Should a diode and/or transistor be used with an automotive (Bosch style) relay for accessory power?
I am a total beginner with electronics, so I apologize if this question has been answered already, I find similar questions but they seem to always be some variant and not quite what I am seeking, so I am asking her... |
H: Is voltage selector on 5v or 3.3v?
I bought this USB to TTL converter and it came with the option to switch between 5v and 3.3v. I want to use it at 3.3v, but I'm not sure where the (grounder?) should be placed? Thanks, see image below. (5v and 3v3 option is on the side upside down).
AI: Based on the photo, the thi... |
H: Duty cycle of 555 timer
I am trying to understand the exact working of this circuit, I have been told that this circuit provides a duty cycle of 50% from my previous questions, the same which I successfully verified in LTSpice simulation also, but when I built the exact circuit on a breadboard and observed the wav... |
H: Building a power strip from scratch
I'm considering building my own power strip for multiple different reasons.
I've been trying to research these, but haven't found much information.
I obviously know what makes up a power strip, but I'm wondering if the copper(?) rails within the strip housing are something you ca... |
H: Configure SPI Slave to handle data coming at the wrong time
I am experimenting with the SPI protocol (fast speeds where 5 bytes of data is transferred in slightly less than 500us) on the STM32F410 configured as a SPI full duplex slave. A master device sends a command byte to the STM32F4 and the STM32F4 responds wit... |
H: Applying Thevenin's theorem between 3 points
I'm studying about transistor polarisation and got confused by this application of Thevenin's theorem, can someone please explain why eT is between B and M and why Vcc stayed even though it's not removed when finding eT? I'm not familiar with using Thevenin's theorem to ... |
H: Relays and mains voltage (Europe 220V+US 120V)
I initially used a DPST relay to switch both the live and neutral inputs of a computer, but someone told me it was a bad idea and that I should only switch the live input.
I live in Europe and here we have power strips with DPST switches. It is mandatory in some countr... |
H: Connecting iM881A-M to Arduino
I want to connect iM881A-M LoRa module to arduino.
And I want to ask which external parts I need to connect it.
In datasheet there are many parts that I think I don't need to use.
Please help me , I am only student.
AI: You will need the filter C1 over the power supply, but all the sw... |
H: How to measure the On/Off current ratio in TFETs and MOSFETs
I saw the conventional understandings other questions: MOSFET ON and OFF current
As I know, the off current is not zero, however very small, in the cut-off region. When we discuss TFETs, one of the critical issues is On/Off current ratio. And the characte... |
H: Voltage divider for a voltage range spanning negative voltages
We have a sensor giving out a signal between -10 V and +10 V, and a signal acqusition device that only accepts voltages between -2 V and +2 V. So we need to scale down the signal into the smaller range. As possible solutions I have identified:
A. Use a ... |
H: I2C bus level shifting
I want to interface with two I2C slaves operating in different voltages. By searching around for possible solutions, I stumbled upon this AN by NXP. Although I understood everything and makes perfect sense, I am still a little skeptic about it for possible pitfalls since I don't want to ruin ... |
H: Digital control stability for more than impulse response stability?
I have a digital control system which is described by the transfer function
$$
Y(z) = \frac{-\beta}{z - 1 + k \beta} X(z)
$$
where \$\beta\$ is a real parameter I can adjust to modify the characteristics of the system, and \$k\$ is a positive real ... |
H: How to calculate base resistor of a NPN transistor that drives a MOSFET?
I'm currently trying to design a circuit that allows me to control a water pump running on 12V through an ESP32 microcontroller. The GPIO pins deliver only 3.3V, so I ended up controlling a NPN transistor (e.g. 2N2222) with the microcontroller... |
H: when should I use a tuned amplifier circuit compared to a LCR bandpass circuit?
I am reading Microelectronic Circuits by Sedra and Smith. When should I use a tuned amplifier circuit compared to a LCR bandpass circuit? The text does not explain it well.
AI: When should I use a tuned amplifier circuit compared to a L... |
H: How to drive a PMOS with higher Gate than Source voltage?
I want to switch on/off a sensor which runs at 3.7V using a logic level P-Channel Mosfet. Unfortunately, the microcontroller which drives the P-Channel Gate is powered with a higher voltage (5V) compared to the PMOS Source voltage.
Please check the below cir... |
H: STM32 HAL I2C always sends 0xFF as first byte when responding to master using HAL_I2C_Slave_Transmit
I have an STM32G4 using the HAL function HAL_I2C_Slave_Transmit to respond with some data when requested by a master on the I2C bus. In the image below you can see the device sends 0xFF followed by the actual data i... |
H: Identify power cable connector
I need help identifying this connector. It looks a bit like a Mate-n-Lock but I was not able to find this layout in their list. I also browsed Digi-Key, Mouser and a couple of auto parts sites, to no avail.
This carries 230 VAC, about 30 mA.
AI: Looks like a 3-pin Molex 3191.
It's ava... |
H: Current mirror with mosfets
This is a current mirror circuit with 2 op amp stages.
First stage on the left
Voltage from a DAC gets fed into U1 which creates a reference current through Rmir (via the N channel MOSFET) by sensing the voltage across Rset in its feedback loop.
Second stage
U2 (the 2nd stage amplifier)... |
H: DC-DC converter isolation capacitance return path?
For those isolated DC-DC converter bricks like seen in the photo below:
The data sheet specifies an isolation capacitance in the order of picofarads. And in order to meet EMC requirements they recommend coupling either side of the isolation barrier with a cap to r... |
H: Film capacitor identification
I tried to repair a device and these two film capacitors were broken. I can read "393K 250V" on one cap but can't recognise the manufacturer logo due to the scratches.
Could you help me identify the manufacturer? Otherwise I guess any cap can work.
AI: Google is an amazing thing
https:... |
H: Why isn't the input impedance mentioned in the datasheet of the AD8597 operational amplifier?
I am trying to look for a high input impedance op-amp to use as a buffer to prevent source loading.
When I started checking the input impedance value for different op-amps, I noticed that some of the amplifiers mention it ... |
H: Why is my output signal aliased when my sampling rate is decently above the Nyquist theorem?
I'm really confused on what's happening here.
I have my ADC sampling at 44.410kHz and any frequency above 11Khz it would alias the output signal.
The max target frequency is 20kHz for clarification.
What I have checked so f... |
H: Question about mixing battery sizes and quantities
Ok. I have searched everywhere and can't find a definite answer on this:
My first question, Is, Can you mix 2 lithium batteries of different sizes together? (Like mixing an 18650 lithium battery with a 3v coin cell lithium battery). would that be be damaging? What ... |
H: Values of currents in inverting and non-inverting terminal of Op-Amp
In the given solved example from a textbook on electronic devices, the author has use the voltage divider rule after assuming \$V_{s2}=0\$. Clearly for equation 1 to be true, the current in the non inverting terminal \$i\$ must be 0.
Why is this ... |
H: Comparing power consumption of different FPGAs
I want to compare power dissipation of FPGAs from different vendors, the I/O count and the logic resource shall be matched as close as possible when choosing the FPGAs.
I want to create a trivial design that would utilize a big chunk of the logic resource and the I/O p... |
H: Compare register value using logical AND (&) and ==
// Hardware sets a RIS interrupt status bit
if(GPIO_PORTE_RIS_R & 0x10)
{
// Software acknowledges the flag and clears the read-only RIS bit by setting ICR
GPIO_PORTE_ICR_R = 0x10;
// something useful
}
The above code should be self explanatory... |
H: current analysis with pre-carried current in the inductor .- confused
The direction of the reference i(t) current is certain. When we add the pre-existing currents, it will be -12 amperes, thats okay. But why did we multiply it by - (minus) when we integrating the expression Voltage and multiply it by inductance ... |
H: How are other chipmakers keeping up with TSMC if their processes are just the best?
In the news recently was Intel's stock falling 20% because its 7nm processes are being delayed by 6+ months. The argument seems to be that Intel is already behind (since they're using 10nm processes while TSMC is on 7nm processes, s... |
H: Unable to find MOSFET type and specs
Recently I've been trying to fix a motor-controling board in my pool cleaner. After some measuring, I've figured out, that two MOSFETs are behaving strangely and their behaviour varies from the other two paires.
Unfortunately I am unable to find the types and specs of the FETs.... |
H: What parts/sections of a CPU take the biggest number of transistors?
I was surprised to hear CPUs only have a number of ALUs. What are most of the transistors in a CPU dedicated to?
AI: From Quora.com:
How you spend your transistors really depends on the problem you're
trying to solve.
If you open up a 1 billion-t... |
H: Air gap for a coil calculation
i would a help calculating the necessary air gap for a coil assuming an ideal magnetic material:
Cross sectional area of active material = 100 mm2
number of turns= 30
Inductance= 1mH
Thanks in advance
AI: We could just plug numbers into the formula, but it's more instructive to do it ... |
H: Trigger relay at different voltages with voltage comparator
TL;DR - I need help on making a relay with voltage comparator which accepts two reference voltages.
Aim
My project needs to run a Raspberry Pi on solar power. Solar panel will be connected to a power bank which will then be connected to Raspberry Pi.
Chal... |
H: Does multiplying range affect accuracy of an analog to digital converter?
Suppose the built in analog to digital converter of a microcontroller has an operating voltage of 0-5 V. These values are converted to integers ranging from 0-1023. So the resolution is 5/1024.
I want to measure an analog value ranging from 0... |
H: Cost effective way to protect circuit from overvoltage
Which is the most cost effective way to protect a DC circuit that requires 5V input (and draw up to 1A) from external power supply?
Suppose that a careless user can accidentally attach an external power supply and power up with 6-9-12-24V, this situation can li... |
H: Does a 4 pin smd crystal need external capacitors to work properly?
My understanding of how this works is quite poor, I've tried reading many sources but just got even more confused by the terms crystals, crystal resonators, ceramic resonators, oscillators, crystal oscillators.
What I know is that when you have a s... |
H: Zener diode response time
I have the below circuit:
Forward diode D0002 - Datasheet SIJ series for reverse protection and C0001-C0004 capacitors for ESD protection.
Zener diode - Datasheet - 36V reverse breakdown.
Question :
BATT1 is the Vcc supply for certain ICs in my design whose absolute maximum ratings is 40V... |
H: Operating a 12V electric lock with arduino
I have a similar electric lock-style solenoid like this one.
If we trust the manufacturer it draws between 1.2A and 2A at 12V .I'm currently using a N-Channel MOSFET 60V 30A - FQP30N06L it works just fine but it's probably an overkill for this project but it's what I had ... |
H: What frequency do BLDC motors generate?
When BLDC motor is used as generator, how does the amount of poles effect the frequency of the 3 phase AC that it generates? For example, if I had a motor with 8 poles and I spun it at 50 rpm, what frequency 3 phase AC would it generate?
AI: For an 8-pole motor there are 4 co... |
H: I have an LED with no specs, but it does have a resistor. I want to double the voltage
It's one of those "stick anywhere" lights that look like a household switch.
It's powered by 4 AAA batteries and has two-2 inch LED strips connected in series with a 3 ohm resistor(looks like a 1 watt).
I want to cannibalize the ... |
H: Is this a reasonable way to get >50 capacitive touch sensors?
I'm looking to include 50-100 capacitive-touch sensors in a project. I've found these SPI 12-key capacitive touch sensors. Would it be reasonable to use several of these for such a project, or is there a more natural solution?
I'm building a chessboard-... |
H: How much FLASH memory is free for a program?
I'm programming for a STM32F103C8T6 (aka blue pill), with the be datasheet here.
On page 14 it states:
2.3.2 Embedded Flash memory 64 or 128 Kbytes of embedded Flash is available for storing programs and data.
Now mine has 64 KB, however, does this mean I have 100% ava... |
H: Analog Vref for ADC on STM's Blue-Pill
I am piecing together my own ADC example for STM's blue-pill module by reading the reference manual (btw I an inexperienced in embedded development).
The code outline so far is:
void do_adc(void)
{
unsigned int ra;
ra=GET32(ADC_CR2);
ra|=1; // ADON
PUT32(ADC... |
H: Triggering a camera flash with a microcontroller
I took apart a "one-way-camera" for the flash part and found a circuit very similar to the image. For a project I need to trigger the flash with a microcontroller (attiny25/45/85v, low voltage version, operates with 1.8-5v). To do that I simply need to bridge the ch... |
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