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I've got a broken roomba, I've tried new batteries and a working charger. The charger is supposed to output 20V-24W when the roomba is plugged in. the picture just shows how I'm measuring the pow...
Imagine a battery pack with <=60VDC of maximum voltage and a load of up to 10kW of power(the PMSM inverter with the input capacitance of up to 1mF). The load is not always known - could be 100uF...
I am really confused how the terms bit-rate are baud-rate are used in electronics. I never bothered thinking about baud-rate being different than bit-rate before. But recently, one of my teachers t...
I don't know whether this question is on-topic or not but answering this helps a lot of future electronics entrepreneurs like me understand how the product design and development time estimation ta...
Usually, voltage followers are built with bipolar transistors (or with opamps if better precision is needed). In this case, the simple rule says that the transistor emitter "follows" the input vol...
[I’m asking this question out of curiosity. I understand that this aspect of the CAN bus specification is what it is, and can not change.] The ACK bit in any CAN data frame is dominant. Each rece...
I've heard that input signals to digital circuits should be "de-bounced", at least sometimes. What is de-bouncing? Why is it needed? When is it needed? What is bouncing around in the first place?
Nowadays, that I videoconference over WiFi a lot, I've started to notice some trends in WiFi quality. And it seems my connectivity decreases when my microwave oven is on (I work in the same room a...
In the past, a large number of new active building blocks have been proposed and published by many researchers all over the world. In most cases, these new building blocks were used for realizing n...
What happens to the overall accuracy of a resistor if I implement it as multiple resistors in series or parallel? For example, can I get better than 2 kΩ 5% by putting two 1 kΩ 5% resistors in ser...
Despite there are many filter calculators available on the web, I still have difficulties to translate what I need into calculator design parameters. For my application, I need ideally a high pass ...
What value pullup resistor should I use for a pushbutton connected to a microcontroller input? I've seen values from 1 kΩ to over 100 kΩ. Some references just say to use 10 kΩ because it's a "goo...
How exactly is the emitter capacitor C3 helping to increase the voltage gain in the common emitter amplifier below? Is it because for AC signals the emitter looks like a short to ground and that es...
I'm curious about FPGAs and would eventually like to get into them sometime during the future, so I'd like to ask three broad questions to help orient myself: In what applications are FPGAs the m...
It is well known that it is difficult to filter the noise generated by switching power supplies, and this difficulty increases as the PSU is supposed to deliver large currents. For example, in a us...
There is always a mixed response when comparing power management ICs (PMIC) and microcontrollers in the application of power converters (I mean as pwm controllers). What are the advantages and dis...
Although I have done multiple PCB designs which passed FCC and CE equivalents using the MCU's/Multiple MCU's, I have a doubt about how to approach the high speed design using FPGA SoC - main thing ...
In a lot of textbooks, filters seem to be designed around a matching source and load impedance. However, If I have a filter stage between an antenna and an LNA, wouldn't I want the load impedance(i...
Moderator Note If this site were mature, this question would be closed because it solicits opinions, or is too specific about particular models. In the interest of site activity, answers are being...
I want to make a simple 7MHz direct conversion SSB receiver in order to materialize some RF concepts I have been teaching myself lately. My question revolves around the mixer portion. I'm failing t...
I was looking at this design: It uses MC34063 as switching controller. I wanted to adapt this circuit, and I was busy trying to pick R1 value. The datasheet has following formulas: The issue I hav...
I want to include a wirelessly charged battery pack into my design. However, I am worried that the wireless charging could damage my main logic board. What considerations, apart from not having loo...
Why do we use open collector / open drain configurations in circuits? From one source I learned that LED controls are of two types- (1) Push pull,(2) Open Drain.Why do we use and what is actually h...
I need to design a simple boost converter like this: - I want to control duty cycle from another circuit such as an MCU but, I'm unsure how to proceed. My requirements are: - Input voltage 12 vol...
Hello, I am designing 1/4 WL strip antenna for a bluetooth chip and i had some questions regarding the 50 Ohm feed line. Right now I am using a Nordic-recommended 1.5mm trace width and a 23mm + 4mm...
I have a MAX809 with RESET pin connected to the gate of IRLML6344. I will rephrase my question. At 5 V, RESET is also 5 V and the LED lights up. But if I add the fan, RESET drops to 0 V and draws 1...
Consider this statement "A voltage source is heavily loaded",what does this mean? I mean that whether the load resistance is high or there is huge drop in source voltage at load due to internal res...
I've been experimenting with LC filter circuits on the output of a SMPS I recently bought because it was too high for the circuit I'm making. After hooking up many different combinations, I found t...
This is an energy meter reference design guide I found in microchip's website. In a microcontroller how come the registers are specific to the project?Please explain.
Recently I had opened an remote control (RC) toy to see its circuit and found that it operates on 27 Mhz. Not just that toy even many toys operate in that 27 and 49 Mhz band. These days we find eve...
Hi, I built a constant current load following the circuit from https://www.instructables.com/id/DIY-Constant-current-load/ But my op amp gets destroyed after a few minutes. The transistor or the op...
Recently, my home suffered a partial power outage, and due to curiosity and a desire to learn more about residential AC power, I'm trying to understand how the event that took place resulted in the...
Hello. I have a grounding problem on my acquisition system. I have read many articles, app notes and whatever but still could not find a convincing solution for the topic. The acquisition system is...
I'm using a variable duty cycle square-wave oscillator to drive a half-bridge MOSFET pair like this. Upper MOSFET is P-channel type, lower MOSFET is N-channel type: - And, I think I'm getting shoo...
A few decades ago, I found a digital circuit that squares a 4-bit input in an old textbook (perhaps 1970s or 1980s). (The figure below is not the original. It differs from the original in that it ...
What benefit has a differential amplifier when measuring the signal from a sensor that is remotely located such as in this example: - Why can't I use an arrangement like this: -
My step-up converter makes audible noise both with and without a load.I am almost certain it is the inductor, because when I hold my finger on it I can feel vibration and it gets quieter. Unfortuna...
I've built a non-inverting op-amp amplifier with a gain of 101 using this circuit: - My input is 10 mV DC and I expected to measure 1.01 volts at the output but I measure 0.81 volts. What has happ...
When switching a relay there should be a flyback diode. It could be just a diode or diode with resistor in series. I understand there is a difference in the speed of relay switch-off. But what is t...
When should I consider using RTOS in my application? Every microcontroller has a good number of interrupts then what is the need of it?
I've heard that a bootloader is code that runs on a microcontroller, and is used to get your application code onto the micro. How does that work? Is there anything special that needs to be done to...
When writing firmware in C for a microcontroller, how can I directly access a memory location such as a hardware peripheral register, given its absolute address? Is there a way to do this safely an...
I have a signal at 10 MHz produced from a 50 Ω source. How can I match that to a 300 Ω load with low losses without using an RF transformer (space constraints)? Are there any circuits and formulas ...
I always have a doubt that how do firmware engineers dump code into a quad flat microcontroller? For a starter kit there is already connection like USB or some SPI ,I2C headers to burn the code,als...
I can't get my CAN bus application (ISO 11898-2, classic "high speed CAN") working and I'm receiving various CAN error frames. These error frames manifest themselves as sequences of 6 bits with my ...
What is the relationship between the pole zero diagram and bode plot? Case example: a 2nd order RLC low pass filter: - $$\dfrac{V_{OUT}}{V_{IN}} = \dfrac{\frac{1}{j\omega C}}{R+j\omega L +\frac{1}...
How can I acquire electronic parts/items/modules and ensure that there is minimal risk of them being unsuitable for my project or design?
I'm trying to drive a relay according to a 5 V digital signal, using this circuit: It works for a while, but then the transistor fails. When I replace the transistor, it works for a while again, ...
If the external power supply to a device fails, and I can't get the exact model, what do I need to specify to get the right replacement? I can re-use the old supply's connector, but what about the...
