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H: How to control the gain of more than one TDA2030/2050 IC with a single potentiometer?
I am on a project of making a music system which will be able to output 6 speakers. I want to control the gain of each six TDA2030/50 ICs with a single potentiometer.
Here is a schematic example of 2 ICs controlling with a single ... |
H: Automatic CAN bus termination
I have two CAN busses which are each terminated on each end by a 120Ω resistor, as shown in the diagram below. The CAN bus consists of a CAN high, CAN low and ground connection. To terminate it, a 120Ω resistor connects CAN high and CAN low.
Sometimes I want to use both CAN busses com... |
H: Why the output voltage of a transfer function is not equal to zero when the exciting signal is at the frequency of the zero
I was reading this document and I found something that I did not understand ...
https://cbasso.pagesperso-orange.fr/Downloads/PPTs/Chris%20Basso%20APEC%20seminar%202016.pdf
Suppose the followi... |
H: Timers prescale and postscale
So i understand that a prescaler divides a clock, and PR2 is the period register which when the timer TMR2 reaches the value it increments from 0.
Why is a post scaler needed to divide a non-clock signal.
From the diagram it looks like the post scaler is trying to divide the comparator... |
H: How to fix an N-channel MOSFET that's always on, without using resistors
First things first: I'm very new to electronics
Getting right into it: I am trying to use an N-channel MOSFET as a LED strip light switch, with 12V at 1.5A supplied to the source and 4.5V from a battery supplied to the gate:
simulate this cir... |
H: Circuit analysis technique, is there a different way to solve the question?
The above question I solved it as follows:
But, I noticed the following:
Is there a different method to solve this question?
AI: None of the four stated answers are correct. Using Millman's theorem, the voltage between A and B is 23.377 ... |
H: How does a repeater convert light from a fibre-optic cable into binary?
I'm just starting out in Computer Science and currently learning about transmission of data in fibre-optic cables. I understand fibre-optic attenuation and that a repeater will then take this light and amplify it.
My question is, how is the rep... |
H: Generate N pulse with a fix frequency STM32f107
I need to know how to generate N pulse with STM32f107 without any external sampling.
Could you provide me any good reference?
Thanks
AI: I can think of 3 possible ways to generate N pulses.
The first method is obvious: Generate a PWM with 50% duty cycle using a TIM m... |
H: Switchable current shunt resistor
Looking at the reference design given for INA826 in the image below, what would my best options be if i wanted to replace J8 with something allowing me to switch in R19 (sense resistor) from a microcontroller (3.3v GPIO)? I am thinking something like a FET, but my design knowledge ... |
H: 555 one shot missing a beat
I built a monostable multivibrator circuit with a 7555 chip.
It has 1MΩ and 4.7μF components for timing, giving a pulse width of 5.17 seconds. It also has an RC on the trigger with 10kΩ and 0.33μF for a time constant of 3.3ms, allowing it to trigger at power on. Power is provided by a 5V... |
H: Can a 1S BMS be used for a parallel arrangement of 4 Li-ion batteries?
Currently I am on a Mini UPS for a modem router project. So my router needs a 12V and 0.6A current. I have four 3.7V, 2800mAh Li-ion batteries.
So I need to keep the voltage at 3.7V but I need to increase the total battery pack capacity for long... |
H: Is it damaging to drain an Eaton HS Supercapacitor below its minimum working voltage?
I have a Eaton HS Supercapacitor that is rated at a maximum of 3.8V, but I noticed on the data sheet there is a "Minimum working voltage 2.2 V". Will using the capacitor to power a boost converter that will drain it below 2.2V be ... |
H: Gain of an amplifier
What will happen if an amplifier's gain is not stable? I can understand it may drive the amplifier into saturation, any other reason?
What if the gain is changing in such a way that the amplifier stays in active region, in that case will any distortion occur?
Likely not. But then what kind of p... |
H: Is sum of currents equal to capacitor current for NMOS Inverter with Capacitor as Load?
I found this in my lecture notes and could not understand how drain current is equal to sum of load and (IL) capacitor currents (ICL) given in the figure for a NMOS Inverter with capacitor load. By looking at the direction of cu... |
H: Is a Δ-Y conversion a must?
Can the equivalent impedance be solved without Delta to Wye transformation?
AI: Mesh Analysis
Re-drawn, you can see that there are 5 mesh analysis loop currents:
simulate this circuit – Schematic created using CircuitLab
If you use mesh analysis then set \$V_1=1\:\text{V}\$ and solve fo... |
H: Driving a 5 V logic input from a 3.3 V output
I have a device which requires a 5 V logic input. That input ordinarily needs to be high and the device is activated when the input goes low. I need to drive this from a 3.3 V output (Raspberry Pi GPIO) which is low when the Raspberry Pi is booting.
In summary: when the... |
H: Effects of low voltage on power grids?
I understand that if load is suddenly ramped up on a power grid:
A sudden increase in current is caused by adding these parallel loads to the circuit.
The current increase thus increases the torque required from spinning generation in order to maintain the speed required for ... |
H: Safe to use series resistors for powering common anode RGB LED from single constant current source?
I have a 3-9W common anode RGB LED (https://cdn-shop.adafruit.com/product-files/2524/FD-9RGB-Y2.pdf) and want to vary each leg's voltage with PWM through FETs, namely IRLZ44Ns, and an Arduino, in a similar config to ... |
H: How To Save A Matrix In Flash Memory In STM32
i'm new in stm32 and in embedded world in general. I'm using a nucleo64 f446re and I want to save a matrix in the flash memory.
Can I use CONST to do this?
AI: Yes, declaring your array as const in C language will leave the data in program flash memory area and access i... |
H: Is Millman's Theorem approach here correct?
The question is as follows:
My answer is as follows:
However, per the source the answer is:
AI: Well, if it's of any help, I also get the same numbers as you. I calculated \$V_L\$ to be 4.7646 volts and I got a current magnitude of 1.0654 amps. I didn't bother to calcul... |
H: What is this thermal adhesive? (heat transfer compound)
Well generally I I encounter this thermal adhesive. for example in inverter (brand: allen bradley). But it is different from I've seen before. It is very solid and generally using at very strange places, such as between 2 capacitors or at leads of a mosfet or ... |
H: Inrush current in the Boost Converter during start
I am making a 400V 1kW boost converter but in the LT-SPICE simulation, it is drawing a huge current of 50-60A at the start for 1ms-3ms, but the current comes down to 12A after that.
The inductor current rating is 20A and I will be making PCB trace for 25-30A rating... |
H: ADS1115 ADC input filter - active or passive?
I want to implement an ADC as part of my bachelor's thesis.
The datasheet of the ADS1115 show that there is no filtering done by the ADC chip before the multiplexer. As I read here, it is good practice to use a filter before the input.
I am currently trying to decide o... |
H: How to make a 500-1000ms timer circuit
There are countless applications for delays of a few hundred milliseconds up to a few seconds. I have not been able to find some elegant solution, but I am sure that there must be a way, and that some of the expertise in here has a neat little circuit that is much better than ... |
H: 555 timer Theremin - capacitor choice, and question about mixing signals
I'm trying to create 555-timer based Theremin, but I have a few questions that I don't quite understand. For now, I'm building it on a breadboard (yes, I know it's not the best option), but I don't want to commit yet to some schematic that mig... |
H: Playing a sound when turning off a circuit
For my project, I am looking to have this (mock-up) circuit play a sound, e.g. the Windows XP shutdown sound, the moment it is powered off.
I have looked at capacitors, relays, opto-couplers, and a bunch of tutorials but they all only can delay the moment the circuit is po... |
H: Amplifier noise output against source resistance
I’m doing an experiment measuring the noise output of a two stage amplifier with different source resistances.
I’ve found results for a range of resistances. I have plotted these results noise output in dB against source resistance on a log-linear graph (resistance p... |
H: CMOS inverter: circular reasoning to understand it?
I am confused by a litte detail with CMOS inverter. Note that I am really a beginner in CMOS "theory". Here is the electrical circuit:
At "first view", I understand the principle. If \$V_{in}\$ is high (\$V_{in}=V_{DD}\$), then the PMOS will be open and the NMOS ... |
H: LTSpice transient simulation of LC circuit
I've a question about the LTSpice simulation of the following simple LC circuit driven by a DC current source.
The first simulation (A) looks good from point of view of initial conditions for either voltage cap V(n001)=0 and inductor current I(L1)=0. As shown in the first... |
H: Unknown symbol - sort of distant switch
I have some technical drawings and I am looking for the name of a pair of components (or maybe two disctinct components) whose symbols I cannot identify. I understand one is a type of switch controlled by the other component which is connected to a NI-6008 USB card. The two a... |
H: What is the purpose of transistors in the feedback of this OP-AMP?
What is the purpose of the transistors in the feedback arrangement of this OP-AMP?
I am mostly interested in the purpose and general use of this kind of "trick", and perhaps also what it does in the circuit where I saw it.
The circuit occurs in a b... |
H: Don't understand the current direction in a flyback diode circuit
I'm aware of that, in a circuit, inductive loads need to be protected with a flyback diode because if the circuit gets open the magnetic field will collapse forcing a current flow in the opposite direction.
What I don't understand is that last part: ... |
H: How to select a CC replacement led driver?
I have a led ramp in my bathroom. It's dead. The led driver isn't providing any volts on it's output side.
The previous driver was an EBIR AED06-700IIP44 but I can't find a new one.
It's a constant current 700mA IP44 led driver that supply up to 13V and 6W.
I'm not at ease... |
H: What's the difference between using 3.7v and 9v as phantom for electret mic?
I'd like to pass from a mic/filter/amp circuit with the LM386 and powered by a 9v battery in single supply to a 3.7v equivalent using the PAM8403. In hi-fi audio the phantom DC is 48v. Is there any downside in using a voltage as low as 3.7... |
H: DIY Bluetooth speaker - Some power related questions
I'm new to electronics and I'm making a DIY Bluetooth speaker. The problem I have is with powering the circuit. I plan to use 2 18650 2200mAh 3.7V lithium-ion batteries in series and use an XL6009 step-up converter to boost the 8.4 volts to 12V needed by the TDA7... |
H: Implement boolean function as multiplexer
Implement and as a multiplexer:
How is that working? When I repeat from before:
Y | out
0 | 0
1 | X
So, this means, when Y = 1, then the output = X
I'm not sure how to understand this. So far, I'm only used to things like "if X=1 and Y=1, then out=1".
My issue is probably... |
H: If I have a signal that switches between 5MHz and 4MHz faster than the sample rate of the ADC on a spectrum analyzer
Basically, what happens if your signal is switching between frequencies faster than the sample rate of the ADC in the spectrum analyzer? I have been curious as to what would happen in this case, woul... |
H: How is this capacitor connected between the inverting input and ground being used?
I found a schematic for a lithium polymer battery charging circuit where an op amp is used as a comparator. The battery voltage (adjusted by a pot on the left) is compared with a 3V reference provided by a zener diode. Can anyone tel... |
H: Loud hum emitting from output stage of Raspberry Pi guitar pedal
I've been trying to implement the electrosmash Pedal Pi project using a Raspberry Pi 4 Model B, breadboards, and parts purchased from DigiKey.
For reference, here is the overall schematic of the build:
So far, I've built the input stage, and the powe... |
H: Can we make a transformerless 220V to 12V converter without a Zener doide?
I saw many circuits have a Zener diode, but a guy from Youtube lighted up a 12V LED without a 12V Zener diode in the cicuit.
How is that?
AI: You don't have to have a Zener diode in the circuit if you are powering LEDs.
A transformerless AC ... |
H: Voltage and Current Stability in a Voltage Divider
simulate this circuit – Schematic created using CircuitLab
The voltage divider is used in many circuits such as biasing the base of a transistor, etc.
Why is the voltage in the circuit on the left considered more stable than in the circuit on the right, if the vol... |
H: Should RF output of (30+j10) Ohms be matched to 50Ohms for antenna matching network?
I'm designing a matching network for a 2.4GHz inverted F antenna. I am using an ESP32-D0WDQ6 MCU, and reading from the datasheet, the output impedance for the RF pins is (30+j10) Ohms. (DATASHEET in section 2.5 on page 7)
Should th... |
H: Send Data With Usart STM32
I have to send data using the usart2 in my nucleo64 stm32f446re board.
The type of data I have to send is float but until now I always send uint8_t using this code;
char msg[1];
for(int i = 0 ; i < Nbit*Sb ; i++)
{
sprintf(msg, "%d ", sigTX[i]);
HAL_UART_Transmit(&... |
H: Can a short circuit kill the USB port of a PC?
I use a cut USB cable as a 5V power supply from my laptop.
If the two wires on the other side happen to touch each other, will it kill my USB port?
Just to be cautious.
AI: It could, depending on how it is built, and how you will short it.
If simply shorting 5V to GND,... |
H: Debugging long 1-wire line with Raspberry PI
I'm trying to setup a network of temperature sensors for my house connected to a Raspberry PI. I'm using Cat6 unshielded cable (data + ground running on one pair, 5v/ground running on another). To test. the lines (5v, GPIO4, Ground) from the RPI are connected to a breadb... |
H: Is current waveform of given dc-dc converter correct?
I don't understand how current (in continuous mode of operation ) at steady state is bounded for this dc-dc converter circuit.
What I thought qualitatively that current should keep increasing like this -
My analysis was something like that -
At t=0 ;
We close t... |
H: Why the voltage is zero?
The question is asking to find ID1 and ID2 of the two ideal diodes in the circuit below:
I solved it as follows:
The correct solution is as follows:
I would like to know where is my mistake. Also, why did he assume that the voltage at the anodes to be zero? why not 3 or 2 volts? How did ... |
H: JFET self biasing
I'm learning JFET self biasing. what I've understood so far is the resistor R_s is used to create a bias voltage as shown. since no gate current flows that means no current in R_G so the potential of the gate is Zero because it is like connecting the gate with the zero potential (ground), then wh... |
H: Why the voltage is assumed zero Confusing
The question asks to solve for I and V.
Why the voltage is assumed to be zero?
Here is the solution
How did he arrive that V = 0 volts.
If he says it’s 2 volts would it be wrong? Why?
I am confused.
This example is from microelectronic circuits by sedra smith sixth editio... |
H: Why doesn't function generator documentation ever mention the maximum output current?
The output impedance mentioned, but how does this translate to maximum current? What happens if you short circuit the output of a function generator?
Let's take the XR-2206 for example.
The datasheet states an output impedance onl... |
H: Is there a way to take a battery power source at 7.1volts 15Amps and convert it to 5volts 4Amps?
I'm somewhat new to electrical engineering, I've been messing around with Raspberry Pi and I'm trying to use a 18650 battery pack (2 batteries) to power a Raspberry Pi (and some other things such as a Fan HAT).
I'm tryi... |
H: How to make sure that my compensated attenuator would work for certain pulse widths?
I have an input (one-shot) pulse that has to be attenuated by 1/2 (half). The input pulse would be of variable width in between 1us and 100ms and would have a variable amplitude: one voltage level would always be ground (0V) while ... |
H: Is it possible to use an electrical motor with a constant torque while simultaneously turning against it?
I've been thinking about whether it is possible to have an electrical motor output a constant torque against which one can then apply a force without breaking the motor?
I guess the best example would be barbel... |
H: ± usage and absolute sign ambiguity
This is from the Datasheet for Texas Instrument's NE5532:
Does this mean I can safely supply Vcc- = 0V, Vcc+ = 30V, and let all other voltages swing within that range?
If that's the case, then that would be one of the ways I've been reading these datasheets the wrong way. Values... |
H: How to activate one LED separately in a group of LEDs?
I want to activate one LED in a group of LEDs depending resistance varies linearly depending on the temperature.
I am using variable resistance that Controls how LEDs will light.
LED1 and LED 2 and LED 3 Depends on Variable resistivity
The problem I have encoun... |
H: why does the Stm32f103c8t6 Board need an ST-Link V2?
Well I am starting a course on embedded systems on udemy and it seems I need an M3 or M4 ARM cortex MCU so I can follow on the projects. The course itself recommend the Discovery board, but I was aiming for the stm32f103c8t6 Datasheet
It seems that there's no muc... |
H: Error in constant current sink circuit and current regulator
I have found a circuit online, which is supposed to be a steady current sink:
simulate this circuit – Schematic created using CircuitLab
and every time I simulate in LTSpice, if I change Vc, the current through RL is changed and I don't understand why th... |
H: 0.1 uF in parallel with larger >1 uF to reduce noise from IC
Back in the day when we would use an electrolytic capacitor across the supply of a IC we would always put a 100nf Ceramic in parallel because (if I remember correctly) electrolytics had inherent inductive properties that would not suppress the HF noise on... |
H: Charging four cells in series with a TP4056
I am using a TP4056 module to charge four Li-ion cells in series using four of the modules.
The red wires in the diagram represent wires for positive terminals and black wires for the negative terminal, while blue wires and green wires are used for connections.
When I tr... |
H: TDA2030 strange startup noise problem suppression
As a newcomer in electronics as a hobby field, before starting, my humble request to everyone is to not get annoyed by my questions which sometimes may be little silly.
So lets get started: I have started studying a little about opamps for audio amplifying and the I... |
H: Where is my MISTAKE in my solution?
This is the second time I keep asking the SAME thing. I hope I finally understand.
The question is as shown below:
with its answer:
Below is my answer for part a. PLEASE tell me where is my mistake!
FYI the accurate answer is that both are conducting. But what is wrong with my... |
H: SPST pin configuration
I ordered a SPST switch (Through hole type) from distributors and also download the cad file for PCB layout from the same website. I am now confused with the pin configuration, in the footprints it has 3 holes. Usually the SPST switch has only 2 pins right?. I have gone through the datasheet ... |
H: What is the stability of a digital signal processed by a filter with z-transform?
I have a question from the book FE Electrical and Computer Review Manual by Michael R. Lindeburg page# DE X-1 with its answer as follows:
I tried to solve it as follows:
I don't understand why is it when z = -2 the system is unstab... |
H: Does a battery powered resistor have Johnson Noise?
The mean noise voltage for Johnson (Thermal) Noise is given by the formula:
\$ v_n = \sqrt{4kTR\Delta{f}} \$.
The bigger the resistance of a resistor or the higher the frequency of a voltage supply, the higher the thermal noise the resistor will have. Does the for... |
H: Correct schottky diode selection
So I'm using the LMR16006 DC/DC converter which is suggesting to place a Schottky diode from the SW pin to ground with a voltage rating 25% higher than my input voltage, which is 50V. Hence, the voltage rating should be at least 62.5V.
Datasheet: https://www.ti.com/lit/ds/symlink/lm... |
H: Why don't I need device drivers for a UART to communicate with a Linux box but need device drivers if USB is to be used for communication?
I have a Linux box. I want to troubleshoot certain things and I was told that I need to custom solder pins to communicate using UART as perhaps it doesnt have device drivers to... |
H: Training Kit for SMD components
I created my first circuit with a microcontroller, an stm32f446 in lqfp64 package. However I have soldered such tiny parts and I'm struggling a bit and already destroyed one of three chips I bought.
Is there any kind of training kit? I do not want to spend each time 10 bucks for trai... |
H: Is measurement uncertainty 2 times standard deviation or 2 times standard error?
Textbooks and online sources often say the industry standard for uncertainty is given at a confidence interval of 95 %. This means out of 100 measurements, 95 would achieve the specified value and deviate around this value in range of ... |
H: Correct way to wire USB 2.0 Type C connector?
I'm playing around with building a simple keyboard, that will have just few buttons, nothing complex.
I have decided to use USB 2.0 Type C connector, like this or this.
Now when following USB 3.0 specs, it says we should use pull down resistors on CC1 and CC2 so that ho... |
H: Reactance to varying DC
Input signal (a) is AC.
Input signal (b) is varying DC.
As (b) has a frequency but does not change direction, does the capacitor's reactance have a different effect
than input signal (a)?
AI: A capacitor's reactance depends only on the value of capacitance and the frequency of the signal p... |
H: How to get a clean 50 kHz square-wave with 555 timer (Astable Mode)?
I can't get a pure square wave above a few kilohertz. Everything is fine at the lower frequencies, but I would like a clock speed of between 50 and 100 kilohertz. Unfortunately, there is a distortion on the rising edge. Is it possible? Is that the... |
H: How dense is SRAM compared to random logic?
Modern CPUs always have some on-chip cache, typically more than one level. This takes a lot of die area; static RAM is generally reckoned at six transistors per bit.
That having been said, the preponderance of area taken by static RAM, is not quite what you would expect j... |
H: Output behavior of CMOS
Assume a CMOS-cell, which is an inverter(?) here and hence, the input is connected to both transistors, but please let's treat the transistors independent from each other.
V_0 = 5 V, when upper transistor is conducting and lower not.
V_0 = 0 V, when lower transistor is conducting and upper n... |
H: Newbie Assistance - Understanding Fairy Lights
I'm VERY new to EE and am learning the basics. My first goal is wiring up some small lights for my son's LEGO projects, and am trying to sort out the basics here.
Right now, I'm attempting to piece together a mental model of how wiring up several LEDs work, mostly vis-... |
H: What is the 0V reference for MOV's input protection on power supply?
In some application notes for MOVs I see example usage in power supply design where each input line (N, L) from the mains are protected with a MOV to a ground voltage reference (as well as a differential mode MOV protection between the input lines... |
H: Why does FPGA PCI Express Tx output have on-chip termination of 100 Ohm?
The Intel Cyclone IV FPGA supports PCI Express (PCIe) generation 1, and the IO standard for the Tx output is PCML at 1.5 V.
The Cyclone IV Device Handbook volume 2 page 1-13 describes that the Tx output supports 100 Ohm termination. The relat... |
H: Why does diode keep conducting even after voltage across it is negative
consider single phase two pulse semiconverter asymmetric configuration.
simulate this circuit – Schematic created using CircuitLab
Note the high value of inductance L1.
Let a be trigger angle of SCR, which is greater than t = arcsin(E/Vs). Now... |
H: PWM edges issue on a STM32F0 micro
I have a STM32F051R8 (STM32F0 discovery board) I am trying to use to generate a PWM using a timer and change the pulse width at runtime. My code is:
// configuration
htim1.Instance = TIM1;
htim1.Init.Prescaler = 0;
htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
htim1.Init.Pe... |
H: How can I determine PD for given impulse, based on transient thermal impedance for BJT?
I have (selected) a BJT to work with rectified mains application.
Transistor is PBHV9560Z (600 V, 0.5 A PNP)
https://assets.nexperia.com/documents/data-sheet/PBHV9560Z.pdf
Under normal operation conditions, this BJT can dissipat... |
H: Parallel resistor before voltage amplifier
For my project, I would like to amplify the output from a photodetector for subsequent analysis with an oscilloscope.
The output of the photodetector is a current. Since we are using a voltage-amplifier, we would like to "convert" this output to a voltage by having a resis... |
H: How to ensure signals from multiple different clocks are in phase?
I am designing a pcb where I have a signal of 10 MHz logic signal with 50% duty cycle that might be coming from different clocks. I will be using a pll frequency synthesizer to turn this into a 50% duty cycle 1 Hz signal. Is there any way I can ensu... |
H: Define the purpose of these components in the operation of this low side driver
I am trying to understand the operation of the following low side driver circuit I found in a schematic of an old pinball machine (redrawn for clarity):
L1 is a Solenoid and Q1 is a Darlington BJT (TIP120).
What is the purpose of C1, ... |
H: How much skew correction can typically be applied to DQS during DDR4 link training?
My understanding of the DDR4 calibration process is that DQS is derived from a common clock with a PLL, then passed through a DLL to apply deskew such that DQS and CK edges arrive in sync.
Is there some standard (e.g. JEDEC-defined)... |
H: Parallel-series RC circuit
I wanted to calculate frequencies of filter
The module of impedance which I got is equal
What is the frequency cutoff of this circuit?
I've made a simulation but I wanted to get frequency cutoff.
AI: Passive transfer functions require an impedance ratio just as 2 resistors provide in se... |
H: How Ethernet uses full bandwidth of the link if one host is sending more than one frame for different hosts?
I followed from this question.
We know that modern Ethernet is full-duplex. At the same time, we can send or receive the signal. Suppose I consider one LAN where multiple hosts are connected by different por... |
H: What Does This JFET Do If Vgs is Always 0V
I'm trying to understand this reference circuit that I found in the datasheet for a piezo accelerometer.
I don't understand what the purpose is if the gate and source are common. My best guess after some research is that the JFET provides a known impedance for the output.
... |
H: Trying to understand Integral nonlinearity in DAC/ADC
So here's the definition of INL:
it is mentioned (underlined in red) that one of the lines can be a line drawn between the end points of the transfer function but in (a) that line appears to pass in the center of the perfect transfer function and not in the end... |
H: Light to Sound Device
I need a device that coverts blinking light to sound. What device would this be or called? Can this be done simply without soldering?
AI: Without soldering the next best thing is breadboarding, which is for usually for prototyping but can be permanent if you're careful with not disconnecting a... |
H: Generate AC PWM using DC PWM LM741
Hi all, this is a LM 741 square wave generator. I want to modify it such that the dc input (PWM) (from 0V,5V) to correspond to the AC output (PWM) (from 5V,-5V). So, the dc input duty cycle should be the same as the output duty cycle of op-amp. How to modify this op-amp to do thi... |
H: What is the purpose of these different-value capacitors?
I guess I am trying to figure out why we wouldn't just consolidate these into one single 22.11uF capacitor.
My initial understanding was that each capacitor was better at filtering certain frequencies, but the 22uF capacitor should theoretically always be bet... |
H: ks0108 vs NT7108 lcd controller
I need to replace a LCD display that has built in a ks0108 controller.
I have found a replacement that really fit all the specs (dimensions, resolution, maH, Voltage) but has a Neotec NT7108 Built in controller instead.
on the web i found this source:
http://serdisplib.sourceforge.ne... |
H: LM324N op amp not turning on if the negative input is above certain voltage
I built the following circuit (I'm using LM324N) and am having difficulty understanding why the op amp is not turning on.
Here are some more observations:
When the potentiometer is set to less than 4V, the led turns on as expected.
When ... |
H: Active load vs active diode
It makes sense that when VGS = VDS, the channel resistance (lower slope) is large compared to the resistance in ohmic region (steeper slope,) so a MOSFET can be used as a resistor.
From a previous chapter I know that a BJT acts as a diode when the base is connected to the collector.
As I... |
H: FFC USB Board Design
I'm working on two little pcbs to emulate a USB-C usb A cable by FFC. In the future I would like this designs on other PCB avoiding USB wires and connectors. For this, I want to test it with the next design: with other female USB A cable and checking if the FFC and minipcbs works fine. My quest... |
H: ADF4106 PLL output voltage lower than ATmega8A input voltage
I am working on making a frequency synthesizer getting ~900 MHz out of a VCO, using ADF4106 PLL.
Now, for programming the PLL, I am intending to use AVR ATmega8A microcontroller.
Everything is good, but the problem that I have stumbled upon is, the datash... |
H: MOSFET switch not switching
I'm comfortable using BJTs but this is the first time I've used MOSFETs. I'm having to drive a larger current (>500mA) so it was this or using loads of BJTs to share the load.
I've created the circuit below:
It's to drive an electromagnet at 24VDC. The magnet has ≈ 200Ω so I represent... |
H: Why does my Push-Pull-Transistor blow up?
I'm currently working on a buffered voltage divider, followed by a Push-Pull stage to be able to source/sink up to 500mA per rail.
The whole thing will is powered by 36VDC, then it's split by half through a 10k voltage divider, followed by a NE5532 as voltage follower to st... |
H: Can't use a polygon to define a board shape in Altium. How to do it?
I have this small single layer LED PCB I created in Altium, with a Polygon poured on the top layer defining the board limits.
When I try to create the board shape by using the polygon as reference, Altium says it can't find the complete polygon, ... |
H: Decoding unknown UART
I'm struggling with a project here. I have an Elechomes EC5501 air humidifier that I want to make "smart". When taking it apart, I found out it uses a circuit board similar in most points to this one here.
But on mine, there is a 4-pin connector labeled "UART" that connects the humidifier with... |
H: Is there anything wrong with this SSR circuit?
I am a mechanical engineering student currently interning at a small company. We make solenoid valves and some tests require that we cycle the valves many times. This is a circuit that I came up with for an optically isolated MOSFET relay. Ideally, the IN and OUT volt... |
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