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H: Send float with Serial Port
I'm trying to send float temperature data from stm32f103c8t6 to qt application. When I try tosee value with Keil I can. But When I try to transmit to App I got some error about convering uint8_t to float. How can I send Float data to app with serial port?
//variables
uint16_... |
H: Boost voltage without switching
What I am doing: I am making a wearable device which will use Li-po battery/ies to operate. I am measuring small currents (meaning I want to avoid buck/boost converters). My design draws a current of ~56mA.
What I want to achieve: I need 5V on the device, which should be as voltage-r... |
H: Use of multiple earthings for single installation
For a home electrical wiring, is it acceptable to have to multiple earth rods on different (reasonably apart from each other) locations?
In good practice, to keep earth resistance low, we use multiple earth rods with a distance to maximize efficiency and connect the... |
H: How to convert European 230V circuit to US standard 120V circuit?
Suppose I have a house in Europe. The house is of course wired with 230V, which means it won't work directly with US plugs.
If I acquired US outlets, how would I convert a single European 230V circuit to the US standard 120V as easy as possible?
I do... |
H: Why do we see one, unified memory address space in ARM Cortex-M core based MCUs even though they have Harvard architecture?
Most of the ARM Cortex-M core based MCUs have Harvard architecture (except for Cortex-M0 and M0+.)
The thing I do not understand is that why we see only one memory address space. For example,... |
H: Is it normal that an analog voltmeter has about 7K ohm input impedance?
I have bought 10V 6c2 DC analog voltmeter, and I have tested it with a regulated DC power supply and it measured pretty accurately different voltages, however when I tried measuring the voltages in a simple circuit like KVL (30V DC source, 3 re... |
H: Why did the CS resistor explode in this circuit?
I implemented the following PFC boost converter as shown in the second image and plugged it into 220V with the no-load condition but it exploded at the plug-in. The explosion happened in the sense resistor (R9 R10) the bridge rectifier is burned out and I think also ... |
H: 5V or 3.3V supply voltage for rail-to-rail OpAmp with 0-3.3V output
I have a 0-5V signal that I want to quantize using an ADC with a 0-3.3V input range.
I want to lower the signal maximum amplitude with the following arrangement:
Is it better to power the second opamp with 5V or 3.3V?
Advantages I see for 3.3V:
T... |
H: Designing GPS matching network with TESEO and chip antenna
I am new to designing for RF and have a question regarding the design of the matching network for a GPS module I am working on.
The datasheet of the chip antenna ANT161575ST-1202A1 recommends a frequency tuning inductor of 1.2nH
and the application notes r... |
H: Home automation: Turn on 5V DC 200mA power when cat approaches
Junior's got a drinking problem.
Junior's my cat, and he only drinks from running water.
Pet water fountain pumps are USB power driven (good), but noisy (30db w/ wavering pitch almost, not quite, at C3) and the noise is irritating. So, I want a Junior-d... |
H: How is power consumed by an induction motor calculated based on speed (from a VFD) and torque induced by the rotor shaft?
I've been tasked with carrying out some design improvements on my company's production floor.
There is a flat belt conveyor assembly line, whose movement forward movement is controlled by a sing... |
H: Antenna feed trace keep it short or long?
I am designing a GPS module but am quite new to RF design. I have seen a number of people say to keep your antenna feed line as short as possible. But in the design guide of the GPS module I am using, it says for chip antennas, which I am using, keep the module a minimum of... |
H: How can one pass values to a bus in Verilog without first making a wrapper bus?
I have just defined an SR flip flop, and I need to now define a D flip flop. I am going about this by using an SR flip flop within my D flip flop. However, because I used a bus for my S and R inputs on the SR ff, I don't know how to get... |
H: Why do the leads of some resistors have holes?
Why do the leads of some resistors have holes?
Is it to:
Run a wire through it before soldering? If so, what is the best technique?
Run a tiny screw through it for connecting a tiny lug?
Provide a barrier against conductive heat transfer between the body and the tip (... |
H: How to control/remove "quiescent current" of UniversalOpamp2
In the circuit below, I get a quiescent current (entering positive supply and leaving negative supply of the op amp) of about 497 µA, while the load current is only 5 µA. I am aware that this purported quiescent current has no real-world significance, but... |
H: Op Amp rails to negative supply when supply voltage is +-5V. However, supplying +-12V "overcomes" this railing, and the op amp begins to properly work
The op amp rails to the negative supply rail with +-5V power supply. If I turn up the voltage supply to +-12V, the op amp begins to work properly. When I turn the vo... |
H: Output resolution of PWM H bridge drivers such as L298N
I am working on a project which require a high resolution of the output signal of L298N or similar driver. Is it possible to control the output signal with a 1% resolution or better? What is the typical resolution of such drivers?
AI: A resolution of 1% is 1 i... |
H: How to fill flip flop clock truth table?
I have this truth table that I want to fill, however, I have no idea how to read the flip-flops on the left. Can anyone provide me a minimal example of how to approach this problem?
EDIT: drawing this table as something like this ... will be helpful for newbies.
AI: Can any... |
H: How to connect to camera interface on OVM7251-EAAR-AA0A?
There's a weird connector on the OVM7251-EAAR-AA0A board from Omnivision:
It seems to be 40 pin and 2 cm wide, and from the sensor documentation it's supposed to be a 1-lane mipi / lvds interface.
Does anyone know how to connect with this from any computer?
... |
H: What are these battery power connectors called?
I'm trying to source some battery contact connectors for sliding straight metal strips into. They're the sort of thing that are used in power tool batteries, but I want to use them for a different project.
Can anyone tell me what these are called and any example pa... |
H: Is there any difference between Silicone and RTV
I've used silicone RTV that's intended for use on PCBs and have also used 100% silicone purchased from the hardware store to use on PCBs. I was not able to tell a difference between the two. Everything looked and smelled exactly the same. I know there could still be ... |
H: Effect on sampling time on BER
Just for some background context:
A digital signal has jitter present on it. In this situation there is
only random jitter (RJ), which is unbounded and normally distributed.
When the digital signal is sent to a receiver, there is a bit error
rate (BER). Let's say the BER is 1E-12, th... |
H: Effect of Ethernet PHY interface on the speed of Ethernet
I have been working on this new project where I need to include Ethernet.
But the microcontroller of my project doesn't have any Ethernet PHY included (no MII, RMII, GMII, etc.)
So, I am instead using SPI to interface my Ethernet controller with my microcont... |
H: 74HC74D initial output value after power up
I use a touch sensor (Active Low) to light up a light bulb. here I've used a 74HC74D D flip flop to turn on an off the bulb with the sensor pulse (sensor output is active low which is then converted to a active high with a PNP transistor to make the flip flop work)
my pro... |
H: What explains this bulb/motor behavior?
My son was building circuits with a hobby kit. He tried connecting a small DC motor and incandescent bulb in series with two batteries. The motor is not marked, probably is rated at no more than 6V. The lamp is marked 3V.
The motor shaft spun, but the bulb did not illumina... |
H: Can I replace a P labeled SMD fuse with a K labeled one?
I am fixing an "old" laptop and I needed to replace a broken screen. While disconecting and reconnecting the ribbon cable, I probably shorted something. Now the back light on both the broken and the new screen doesn't turn on.
After some googling and probing... |
H: What's the difference between these two logic diagrams?
I have these two xor logic diagrams, they seem to work the same on inputs which are not even, but what is the difference between them? What is the purpose of it and which one would be faster?
AI: There does not appear to be any logical difference.
The second w... |
H: KiCad: Ground plane won't connect to pads
I am currently running into a problem in KiCad where the ground plane won't connect to some pads.
KiCad even tells me to connect them but doesn't seem to make the connection automatically.
AI: I just checked the settings of the plane and realized that pad connections were t... |
H: What is the purpose of the capacitor and diode in this fan driver circuit?
I have an FPGA dev board with a fan PWM circuit so that you can hook it up to a fan + heatsink. I happen to like this as we put a common heatsink together for the hottest components, and I drive it from the FPGA based on the FPGA's internal ... |
H: Odd results from mesh current analysis in a circuit with a diode
I have this circuit:
simulate this circuit – Schematic created using CircuitLab
The reverse saturation current of the diode is 10^-6 A.
I use mesh current analysis to find the current inside the diode:
And putting this into WolphramAlpha gives I2 = ... |
H: Conditions in Timers (STM32F103C6)
I am developing a project on STM32F103C6 and am new to it. I've implemented a timer with interrupt, which checks the temperature value measured by a sensor(LM35) every second, and if it is more than 38 degrees, the system triggers a buzzer.
The system triggers the buzzer as expect... |
H: Unidirectional level shifter 1.8-5V -> 3.3V
I'm looking for a circuit/IC to shift logic levels between 1.8/3.3/5V and 3.3V.
This is to connect various devices via UART to the ESP8266. As such, I only need unidirectional translation - the ESP8266 TXD operates at 3.3V and should be shifted to 1.8/3.3/5V according to ... |
H: Why does Altium not permit changing net names from schematic view?
Here is a short snippet from the schematic view showing the righ click menu from a net and the net properties:
Altium shows Physical name and Net name for the net. However, there is no way to modify them in here. This is quite puzzling. This brings... |
H: How to unplug these connectors on 80's amp/receiver
I'm trying to unplug these connectors to get access to the lcd display.
Do I need a special tool? I tried but to no avail. The little ones seem fragile. What is the name of these connectors?
AI: I have seen ribbon cable connectors like that before. They were origi... |
H: Does a demultiplexer affects as a PWM would do?
I'm designing a circuit which has to display 8 numbers. I pretend to do it with 7-segments displays. I dont have enough pins in my MCU to control every single display independently, thus, I will use a demultiplexer.
The thing is, using a demux, only 1 display can be "... |
H: Stand-alone ESC v.s. BLDC driver ICs, what's the difference?
I am designing a customized miniature drone for research and would like to embed the ESC for BLDC motor directly on board to save space and weight. I have searched a lot for ESC design online and can understand the basics to the point that I think I can i... |
H: Buck converter bias supply
I am using an MP2325 buck converter (datasheet) to drop a 24v supply down to 5v to supply a Raspberry Pi.
The datasheet above details Pin 7 as VCC a "Bias Supply" (page 7) and mentions nothing else about that pin in the datasheet.
I have found this app note from TI: Benefits Using a Buck ... |
H: Antenna: three element array, Balanis problem 6.3
I am trying to solve the below Problem (only question (a)), where I am mainly stuck on figuring out how to read this z/y drawing of the magnitude and phases.
The problem has to do with 3 antennas called "three-element array of isotropic sources". We always assume fa... |
H: Is possible to overwrite a Serial NOR Flash sector without high memory usage?
Introduction
I am developing a high level library to read and write for winbond W25Q512JV and ATmega32U4 mcu.
From the flash datasheet:
The Page Program instruction allows from one byte to 256 bytes (a page) of data to be programmed at
p... |
H: Kelvin connections in PCB
in the following webinar from youtube, a recommendation is presented about the kelvin connection at the 41st minute of the video. but I couldn't get it. (second language)
https://www.youtube.com/watch?v=gq-0ZpcGm8E
why those vias are placed? where is the other end of those vias connected? ... |
H: Do circuits with pull up resistors waste more electricity than circuits with pull down resistors?
A pull up resistor provides a constant voltage (and therefore some current) to an input pin on arduino.
https://learn.sparkfun.com/tutorials/pull-up-resistors/all
A pull down resistor connects an arduino pin to to grou... |
H: Help troubleshooting an unstable 595 shift register
Summary
I am looking for help troubleshooting a couple of shift registers that seem to be unstable in a digital wall clock that I've built back when I was active in this stack, back in 2014.
More than fixing the clock, I'd like to learn how to troubleshoot and ide... |
H: Term similar to "gain" for voltage dividers
In amplifiers, the magnitude of amplification is called "gain". Is there an equivalent for that on how much a voltage divider divides? Like how a voltage divider with a 100k and 39k resistor has a "divide" of 0.2806.
I wasn't able to google any results so I've come here.... |
H: Flux in V/Hz to actual motor constant Ke?
I have some trouble to calculate the motor constant Ke in V/krpm from a known flux constant of the motor. The motor has a rated flux of 0.249V/Hz and 2 PP (pole pairs).
I already know, that Ke is 9.8V/krpm, but I do not see, how I can calculate this from the above rated flu... |
H: Using an oscillator instead of a crystal on W5500
I am designing a circuit I am planning to have fabricated that uses the W5500 Ethernet IC. I am quite new when with this and I've heard of a number of people having problems with the crystal (bad tuning, no start, etc.) that goes with the W5500.
I need to get this c... |
H: Water level indicator using CMOS inverter
I want to build the below circuit. The circuit has three levels to indicate water. low->o/p LED. Medium->O/P LED. High->O/P LED + Buzzer. Each level has two types of MOSFET; they work as CMOS inverters.
What to use for the N-mos and P-mos? If you could give me names; I want... |
H: Can simple DC/DC linear regulators be used in parallel?
Can linear regulators such as the L7805CV (Rated at 5V output, 1A max) be used in parallel? I need to create 5V from 12V, but I need more than 1A, so a single regulator won't do. Can they just be wired up in parallel to achieve a higher maximum current?
simul... |
H: Is stall current generally equal to inrush current?
I haven't been able to find a clear or definitive answer on this, and I've been wondering about it for some time now:
Does the peak inrush current of an electric motor equal the peak stall current of the same motor?
In my mind, it would make sense if they're the s... |
H: 0 current in a circuit using tunnel diode
Suppose we have a diode with negative differential resistance of -40 ohm in the region of 0.3-0.5 V and we put it in parallel with a 40 ohm resistor:
simulate this circuit – Schematic created using CircuitLab
Now Rt = R1*R2/R1+R2 = -1600/0 = infinity. So no current should ... |
H: How is the winding cross-induction of a 3 phases motor magnetically interact from one winding to the next?
Considering a Squirrel Cage 3 phases motor. A multi-switch receive the 3 lines of the 3Ø power L1 L2 L3 and distribute the voltage to 6 wires. The multi-switch has 3 position, Speed 1 , OFF , Speed 2, or Low ... |
H: 240V Mains - Current draw and when to use Solder vs Welding
No specific application, just for interest - I opened up a multiplug/multiboard and noticed that all the contacts for welded (i.e. no solder). I was just wondering if this had anything to do with current draw, and (if so) what's the upper 'safe limit' for... |
H: Synchronized two frequency source seems to have phase drift
I have two arbitrary waveform generators which are synchronized at the external but shared 10 MHz clock. My research experiment importantly uses phase-sensitive signals.
The problem I observed is that even if they are set the same nominated frequency (for ... |
H: How to reverse voltage 12-24VDC to use a peltier element for heating and cooling
I'd like to use a standard peltier element as a heater and a cooler. The specs should be something around 12VDC, 30W. Electromechanical relays are not an option, the peltier should be used to regulate a temperature for many months. The... |
H: How to disable the Temperature Sensor Si705x
Is it possible disable Digital Temperature Sensor — Silicon Labs Si705x by software? I want save energy.
AI: Reading the datasheet, I’m observing that the chip comes out of standby only when processing an I2C command or doing a temperature measurement, as commanded via I... |
H: Can a bipolar capacitor in an AC circuit store even a tiny amount of energy?
I've been reading (some Q&As on here and other bits on the web) about the behaviour of bipolar capacitors in AC circuits.
I understand that a polarised capacitor cannot work and will likely explode in an AC circuit due to the voltage going... |
H: Ethernet Switch configuration mode
I'm trying to understand the Ethernet Switch product.
On page 54,55, we can see that, the MAC signals, Like for MII and RMII interface, we can understand that the digital MAC port 3, can be configured as either in MAC mode or PHY mode.
But for RGMII interface, there are no 2 separ... |
H: Collector resistor value affects the delay in this simple turn-off delay circuit. Why?
Here's my simulated circuit:
As you can see, when plotting the output voltage, the smaller the collector resistor value is, the shorter is the delay.
But why? What BJT graph predicts this behavior?
Thanks in advance.
AI: The low... |
H: Fault impedance type?
Usually fault impedances are resistive type. But is it possible to have a mix of resistive and reactive component in fault impedances? Looking at many simulation tools, they give the possibility to apply a reactive component to the fault impedance, therefore I think the answer is yes, but are ... |
H: PSRR of an amp + ADC input stage
I have an input stage that consists of an amplifier then an ADC. The op-amp and ADC are powered by Buck voltage regulators.
I want to measure the PSRR of this stage, so I am planning on breaking the power line and adding a 200mVpp AC signal in series and see the effect of this sign... |
H: How to use panel-mount connectors where the nut goes on the inside of the panel
Some panel-mount controls have the nut on the outside of the panel, like this:
Other panel-mount controls have the nut on the inside of the panel, like this:
With the nut on the outside, I first solder everything while it is outside o... |
H: Why can't current change instantaneously in a given inductor?
I know the mathematical reason behind this. Given the inductor I-V characteristic we know that:
I understand mathematically that a function which is differentiable must be continuous, but what is the physical reason behind this?
We know that current cre... |
H: What would it mean if a circuit board all of a sudden works after it doesn’t work for some time?
Sorry for my noob question. I am very new to debugging hardware circuit boards.
A circuit board was not working. After measuring a voltage rail it was jumping from 12V to 0V, and back to 12, etc. what kind of behavior d... |
H: Help Understanding Opamp Topology (Infinite Gain Multiple feedback with Resistor to Gnd?)
I ran across the following band-pass circuit and I'm not entirely sure what R14 is doing here. The following is a screenshot:
For some context, the supply is a dual rail +/- 3V3 and the input is a 100 mV peak-peak, zero-cente... |
H: LTspice AC analysis extracting only the phase shift value at a certain frequency
I am trying to extract the phase-shift value at a certain frequency in AC-analysis mode in LTspice.
.meas AC Ph_Shift FIND (V(out)/V(in)) WHEN FREQ=50
With the command above LTspice gives the answer line below in the log file:
ph_shif... |
H: Which of two Verilog lines is preferred?
If we want a modulus 10 counter (counts from 0 to 9), we can write this:
reg [3:0] cnt = 0;
always @(posedge clk) cnt <= (cnt==9) ? 0 : cnt+1;
optimization is available if we realize that we don't actually need to compare all the 4 bits of the counter to 9. The code below u... |
H: Trace to Pin connection
I am having the issue of connecting my voltage regulator to the trace. The trace must be thick but the pins are too small.
What is the best solution? I am using proteus. Does making a solder Paste shape work?
Thank you!
AI: A trace's resistance increases with length, and decreases with thick... |
H: Finding DC saturation behavior of clamp ferrites
While some chip ferrite datasheets specify maximum current and DC saturation behavior, it seems like many clamp ferrites omit both maximum current specification (which arguably is less critical) but also any notion of the DC saturation behavior.
In my case, I'm looki... |
H: How to safely protect input sensing AC Line Voltage
I'd like to detect the presence of AC line-level voltages in my PCB project, and I'd like to follow best-practice for doing this. I'm a controls engineer so I'm happy with dealing with mains with chunky discrete components, and I've done a bit of DC electronics an... |
H: What happens if you connect an AC generator to an AC motor?
An AC generator (or alternator) converts mechanical energy into electrical energy. An AC motor does the reverse.
What would happen if we connect the two in such a way that the output rotational kinetic energy of the motor becomes the input of the AC genera... |
H: Phase of type 3 compensator
I was supposed to simulate a type3 compensator but i got different result from PSPICE and HSPICE.I have no idea why??:(
PSPICE:
HSPICE: shape of gain is the same with PSPICE,but shape of phase changes like below.(I dont have the simulation result pic but just like this)
AI: Shape of pha... |
H: LTspice and op-amp strange behavior
I noticed a strange behavior using TL074 and I made this simplified block to verify my feeling. Opposite to what I see on a breadboard, I think the output(s) are totally wrong, but I cannot believe a so dramatic result, so I assume I am terribly wrong somewhere.
On the breadboard... |
H: How to determine phase sequence of the unbalanced three phase grid?
Let's say I have three phase voltage grid which is unbalanced (three phase utility grid). The phase voltages are sampled by the adc (suppose that the analog channel is properly designed from the hw point of view and the sampling period is set prope... |
H: Electrical circuit with 3 voltage sources and a current dependent voltage source
I have this exercise where I need to say if the circuit is possible to be connected.
I'm in doubt cause we can't connect different voltage sources in parallel, but this current dependent voltage source and the current source is bugging... |
H: Bandpass filter doesn't work when implementing PCB
I have been trying to make a 5th-order Chebyshev filter going from 500 MHz - 570 MHz and a 3rd-order Chebyshev filter going from 500 MHz - 540 MHz. This is my first time making a filter into a PCB.
No matter what I do, my physical implementation of it doesn't match... |
H: How can I adjust the imported 3d body in Altium designer?
I've downloaded and imported the following SMPS transformer 3d model into Altium designer but it doesn't fit my footprint how can I adjust it by changing scales and moving pins?
AI: Imported models cannot be scaled. And also subsets (bobbin, pins, core etc.)... |
H: SR latch circuit with ESP8266
I want to keep some state during a deep sleep of an ESP8266. To do this I used the following SR latch circuit:
It works well. The only change I made is that I used 2N2222 transistors.
The only problem is that this circuit uses S1 and S2 switches to change the state. On the breadboard ... |
H: What is a suitable battery to power five servos?
I have five Futaba S3003 servo motors. I want to run them simultaneously. What battery should I use?
The datasheet says:
Current drain (4.8V): 7.2mA/idle
Current drain (6.0V): 8mA/idle
I'm not sure if the ampere value is right. I think it is too low.
Can someone ... |
H: The output of PI controller using opamp is not working
I am designing a closed loop system for dc-dc converter for that I am using error amplifier and pi controller. For error amplifier and PI controller I am using OP177A opamp. The error amplifier output is coming exactly as per requirement and gain setting. But ... |
H: KSZ8081 PHY address configuration
I'm using this KSZ8081 PHY transceiver.
I'm unable to understand how to configure the PHYAD[0:2] pin and the B-CAST_OFF pin.
As far as I read, the PHY Broadcast address will always be "0" and the unique address of the PHY can never be "0".
So, when I pull down the pins of PHYAD[0:2... |
H: Disturbance in AC adapter
I'm studying AC adapters, and to check about waveforms while changing parameters I did a simulation of this circuit:
simulate this circuit – Schematic created using CircuitLab
Then I wanted to plot also the rectified waveform, so I added a second diode and a big resistance (sorry if this ... |
H: What does it mean to assign a conductor?
I am reading about SATA power here.
They say the following:
The power cables for the SATA interface are of similar construction as
the signal cables, but have 15 conductors. They supply power to the
hard or optical drive at the voltage levels of 3.3, 5 and 12 volts.
Each vo... |
H: Hamming code error correction multiple bits
If we send a message from a sender and the noisy channel produces 2 bits with error can we detect both bits using hamming code or is it just for 1 bit?
AI: The decision to "only detect" or trying to "correct" the errors changes what you can do with 100% coverage:
if erro... |
H: Can the polarity of a 12V brushless CPU fan be reversed?
Can the polarity of standard CPU 12VDC brushless fan be reversed? For my application it is fine if the fan is not broken afterwards. Please see the image of the fan below:
AI: Can the polarity of a 12V brushless CPU fan be reversed?
For a simple fan such as y... |
H: LM317... Do we need resistors?
In the circuit below, I replaced LM1117 with LM317. Do I need to add resistors at the output terminal? and how can I calculate the output voltage in this case?
AI: LM317 needs resistors to set the output voltage, so yes, you need resistors.
The method of calculating resistor values ar... |
H: How does this PNP transistor improve the switching performance of MOSFET?
My guess is PNP transistor might ensure fast turn off by shunting the gate capacitance (ie, when diode is reverse biased and the PNP is on.)
Additional questions:
Why is the gate current limiting resistance not present?
What is the role of... |
H: TEC cold side temperature decreases, then increases rapidly
first post to this stack exchange.
Self teaching on TEC circuits. I bought a diymore TEC1-12706 12V 60W 6A. Note no heat sink installed on the TEC. To test the TEC I put together a series circuit as follows: battery 12V/8AH/10A max discharge, 100(Ohm) resi... |
H: Can an opamp have a negative gain?
I have a school excercise which I don't fully understand. The excercise is that you build an opamp circuit with a negative gain, -40 and a bandwidth of 100KHz. The gain-bandwidth product is 1000 000.
If I calculate the GBP -40 * 100Khz = -4000 000, so I have to split my opamp up i... |
H: Optocoupler necessary when grounds already common?
I have a 24V solenoid device, that is able to push and pull a small pin, that I would like to control with a 5V micro controller.
The solenoid has a reed switch connected to 24V that indicates whether the pin is currently out or in. In order to read this with the m... |
H: RF high power amp bias scheme
I am using the TGA2237-SM for the TX side in a front end design. I am trying to figure out an analog method for doing the bias up and bias down procedures.
Bias up
Set gate to Vg=-5V
Increase Vg till Id=360mA (drain current), Vg~-2.6V
Apply RF
Bias down
Turn off RF
Decrease Vg to -5... |
H: Basic IR circuit question
I'm creating a basic IR circuit and trying to get a better understanding of its working.
What is the purpose of R2? and how would I calculate a new value for it if I was using a higher voltage supply instead?
AI: In the absence of R2, all the current flowing through D2 would pass into the ... |
H: Power Supply Module Internal Trimmer circuit / Remote Programming Resistor Value?
I am looking to incorporate a 45V supply into a design. These PFE1000-48V supplies have a trimming ability to get +/- 20%, based on +/- 20% variable resistor. I am trying to confirm what this resistor value should be. If 45V is 93.75%... |
H: Help with identifying SMD ccomponents
Can someone help me identify a couple ofSMD components?
Both are from analog circuits.
The first package marking is 50W.
I'm assuming that it is a JFET, but I'm not sure.
The second one is marked A6. I'm assuming that this is BAS16 diode, but the package looks not so usual to... |
H: What are the names of screens used in "Basic calculators"?
I was trying to power a basic calculator that day with a power source and I started from 0V going up to 1.5 v I noticed the calculator screen turning out to show a "0", but I could not do any calculations. I also, noticed that powering the screen did not ev... |
H: Can I power an external stepper motor driver while stepper motor is disconnected from driver?
I am building a laser cutter and I am using external stepper drivers to power stepper motors. I have a driver for an optional stepper motor for a rotary attachment. I would only disconnect or connect the optional motor w... |
H: DIY Multiplexing circuit to drive 7-Segment displays like they did in the 1970's
My old CMOS cook-book shows a generic block diagram for a MUX circuit to drive many 7-segment LEDs.
It's assumed the reader will use an off-the-shelf MUX chip to drive the displays, but I don't want to.
I want to build my own circuit u... |
H: Should I use heat shrink tubing on solder connectors?
I learned soldering after IPC-J-STD-001 E during my apprenticeship 10 years ago and my instructor told me that you don't use heat shrink tubing on connectors, but recently I've seen a lot of this and some of my colleagues say that you should do it.
Let's say you... |
H: Bigger NTC = better protection?
A 2.5 ohm NTC is used in the following PFC booster. I've got a 20 ohm one. Can I use it instead of 2.5ohm one? Does it provide better protection or does it disturb the normal operation of the circuit?
AI: A bigger resistance NTC thermistor will reduce the inrush current on power up (... |
H: Does the input offset voltage of an opamp remain same after each power up?
If we have an opamp and we know the input output relation we can obtain a linear function even though there is input offset voltage.
In the above situation as long as we know Vio, and since resistors are fixed we can derive a transfer funct... |
H: Why is the output voltage in my second op amp not the same as for the first op amp?
I saw this tutorial on a website.
From that, I designed these circuits:
In my circuits the voltage source is 12 volts.
The tutorial says the output gain should be 2. In my second circuit the gain is 2 but in the first one that is ... |
H: bi-directional motor using SPDT relay and diodes
I have a bi-directional motor that I am trying to control using an SPDT relay. It is only working in one direction when I remove the circuit for the opposite direction, and it is either shorting or just not starting no matter what I try. Below is my circuit. Any idea... |
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