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I'm supporting a piece of legacy hardware that routes the SPI bus through a set of headers to an expansion board. Since the expansion board doesn't actually use the SPI bus, we simply ignored the ...
There are various different methods to keep common mode currents off the cables, one of them being discussed on the site here and with Olin's decoupling caps post on StackExchange. Slight digressio...
Im studying the equivalent model of a BJT common emitter amplifier at high frequencies.At university we tought that the BJT at high frequencies looks something like this: However when designing ...
We see schematics of varying quality and conventions. What is good and bad? What are the rules and conventions for drawing good schematics? What matters? What doesn't? This question is about sch...
I have a Rigol DS1104 oscilloscope. Last week I stood up quickly from my table and saw a spike on the scope. Right now all the channels have a DC offset when probe is connected to ground or unconne...
I have a non-invasive current sense transformer (SCT-013-030) which according to its datasheet it is voltage output type. I want to harvest energy and supply a wireless sensor that consumes 5-6 uA...
Suppose we have a RC low pass filter of 1st order. If we add multiple stages every time we add a RC stage identical to our original does the slope of the curve in the bode plot db/Hz becomes wild...
Problem pH electrode buffer offset appears when solution is grounded. Detail I have a pH electrode in some conductive solution (~1000uS). The output (measurement electrode) is buffered by an el...
I'm looking for input from anyone with insight in the PLC world. How do PLCs usually measure 4-20mA current loops? I would assume it's one of these two alternatives: Through an external "shunt"...
The plugs for microphones and for earphones are the same, however their functionality obviously is quite different. Now because of the same plugs it is easy to insert one of them in the wrong socke...
Im designing a high-pass filter which has a gain of -8dB at half of the roll-off frequency and I am stuck ,I dont know how to continue the design. In the bode plot of that filter we have 2 points:...
Assume I'm a complete beginner at RF. Is there a way to measure return loss of an antenna, in such a manner that I can reliably reproduce the measurement later on? What I'm talking about is produ...
I want to find the conditions of oscillation of the following Hartley oscillator.I have attached a load (ZL) to my Hartley oscillator I have written KCL for nodes A,B: For node A: $$\frac{V_{A...
I am looking to improve my knowledge of embedded systems programming, specifically regarding microcontrollers and embedded Linux systems. A lot of the information that can be found regarding C/C++...
I am generating files for manufacturing my design in Altium 22 and ordering through Eurocircuits. What I noticed during the ordering process is that the rotation of many components (and sometimes ...
Im designing a Hartley oscillator this time with a opamp providing the open-loop gain.I have tried drawing the small-signal analysis of my circuit to use KVL and KCL to find the conditions of opera...
The small signal analysis of a BJT when the BJT is in amplification mode: is easy.However what happens when the BJT is in saturation mode? Can we replace the dependent current source with a r...
First I noticed that clock begins before chipselect gets pulled low on SPI. After eliminating potential sources I started to suspect the scope. I connected all 4 channels to function generator at d...
I am trying to find the AC analysis of a BJT Hartley oscillator but I cannot continue. How do I find the voltage gain? When no feedback is there, we just find the output resistance and the current...
I am designing a low-pass filter with cut-off frequency = 100Hz and after the cutoff frequency from -3dB to -10dB the average decrease in db/Hz = -0.1 db/Hz.I know how to design a low-pass filter ...
Signals with frequency above the cutoff frequency of a transmission line cannot be transmitted through the transmission line. But how can I calculate the cutoff frequency of a single phase transm...
I was studying the Re model of a transistor: But the Re model for 2 different configurations (common emitter and common base )turns out to be the same! I don't know why I am really confused.How...
I have designed a PCB that I need to work in which a microcontroller drives a 24 V brushed motor. The input power to the board is 24 V, this is then lowered to 5 V by a step down converter, and thi...
I was watching a video from EEVBLOG about bypass capacitors, and he presented a theory that randomly connecting different values of capacitors in parallel can create unexpected impedance spikes: ...
I saw that equation of reactance is written like this $$I=\frac{V}{|R+X_L j|}$$ $$I=\frac{V}{|R-X_c j|}$$ When there's capacitor and inductor in a single circuit then it is written like : $$I=\...
I'm designing a high side current source that can be controlled with a Digital-to-analog and can source up to 100mA with voltage supply up to 36V. By high side I mean one side of load will be alwa...
Which important system design parameters need to be locked in order to estimate the maximum allowable level of the input voltage ripple of an SMPS? I have encountered ballpark figures of <1%, &...
I saw that this PCB socket: Is marked as pressfit for non-plated holes. However, can it be used with plated holes as well, or will it damage the plating inside?
Suppose we have a sine signal applied to a inductive load. Is the inductance of the load changed if the frequency of the signal is changed?
The premise In a recent video by the pop-sci channel Veritasium, the concept of the flow of electricity and energy transmission in a circuit was discussed. In that video a thought experiment is pr...
I was looking at different transistors, especially MOSFETS and I saw that N type MOSFETs seem to be way more popular to be used in circuit design. Is there a reason for that, or am I mistaken?
I recently started working at a construction office in another country. I usually listen to music when working, and I saw a headphone jack in the wall, so I thought it is radio or something, I plug...
I have designed a graph of the current in a photoresistor related to the brightness of light which hits the photoresistor. Our professor told us that it is more correct to draw the Current/Brigh...
As we know there exists numerous different kinds of PCB CAD software. The big ones seem to be Eagle, KiCAD, Altium, OrCAD, Solidworks, DesignSpark and probably a few more. When it comes to mechani...
RF novice here. If using a superheterodyne receiver for the purpose of FM/FSK modulated signals, I'm wondering if the location of an optional automatic gain control (AGC) circuit is always placed o...
I need to design a simple flyback 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 125 ...
I have a PIC32MZ2048ECG064, a 64-pin 32-bit microcontroller with 512kB RAM. This is not enough for my purposes, I need to extend it by at least 32MB, preferably 64 or 128. I believe this means I ca...
On the LEFT is what I just bought today — Globe Electric 4W (40W Equivalent) Daylight (5000K) Dimmable LED Light Bulb, G9 Bi-Pin Base, 400 Lumens, 15,000 H. Here's Globe Electric's Dimmer Compatibi...
One standard used for spacing conductors based on voltage is the IPC-2221. This standard differentiates spacing requirements for inner and outer conductors. Does the IPC minimum separation betwee...
Differential pairs, such as for ethernet or a CAN bus, can be designed to be loosely coupled or tightly coupled. For a loosely coupled differential pair, the odd-mode and even-mode impedances are ...
I am designing a PCB with somewhat limited space. To save space, I am placing some vias on component pads. However, I am not sure if this is a good practice in PCB design. As far as I understand, t...
In a 3 phase Star source-Star load circuit the phase voltage has different phase than line voltage and in a 3 phase Delta source-Delta load circuit the phase current has different phase than the li...
Assume a app generates a message (stack on computer).Each layer of the sending entity will put then control information in the data depending on the protocol and transmit the data to the next lowe...
The question: Is there a way to convert from triple-phase 208VAC to single-phase 208VAC? Background: Hi everyone, I am stuck on a project I'm working on. I'd like to convert 208VAC (three phase,...
I have a handheld ARM Cortex M based device, which has a USB input port. The product is battery powered and there is no metal chassis. We are going through CE testing, and are having ESD issues a...
In this datasheet it says that the minimum resolution is 0.1uA for the 10mA range.What is this minimum resolution?Is it the sensitivity of the multimeter for the 10mA range?
Can we find the internal resistance of a multimeter ,when we use the multimeter like a ampmeter, from its datasheet? I am trying to find the internal resistance of IDM 505 and I went to the datash...
I'm wondering if there are particular aspects of an oscilloscope probe's performance that tend to suffer, or failure points to look out for, if/when buying lower-end makes of oscilloscope probes (l...
The circuit above is used to control a 240W ceramic heater by means of a PWM signal at 30Hz, generated by a microcontroller, with 5V logic. The input is a standard 280W AC-DC external power adapt...
Hello everyone, I have a simple circuit in which I control some LEDs via an MCU and DMG2302UK ( N-channel MOSFET ) The EN pin is connected to an MCU gpio pin that works at 3.3V. The circuit wo...
