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Hi,
I will try to draw it.
A constant current source can be made with a zener diode between the base and GND, but the current in the base will vary with the voltage on RS232 line.
I have a +5V available.
Hi,
I didn't find a solution yet.
The purpose is to add LED on RS232 signals (breakout box).
With transistors the base current will vary with the RS232 voltage applied, so the loading on the line will vary. Would it be possible to use JFET current sources for the LED, so with 2mA LED it should...
Hi,
I would like to have a red LED ON when the voltage on a line is between +3V and +15V and OFF when the voltage is between 3V and -15V.
And the same thing with a green LED : ON when the voltage on a line is between -3V and -15V and OFF when the voltage is between -3V and +15V.
Is it possible...
solder resist
Hi,
I've read the following in IPC 2221 :
What does it mean? That it is possible that the solder resist couldn't adhere to a track > 1.3mm? If so what does relief
through the metal to the base laminate substrate mean?
Thank you.
on creepage and clearance
Is 0.7mm for clearance, for creepage or for both?
There is a solder resist, but no conformal coating.
Must the distance from pad to pad be greater than 0.7mm since there is no solder resist on the pad?
The heatsink is a vertical one soldered to the PCB and has no...
triac soldering temperature 220vac
Hi,
I have to do a PCB with a triac (TO-220 isolated package) and an heatsink.
The maximum current is 9A. I've found tables for the track width but how can I choose the tolerated temperature rise in order to calculate the dimensions of tracks?
I've seen a...
formulas for triac
Hi,
I know it is a triac power dissipation formula. It is from Philips AN10384 application note. But I would like to know where it comes from (theoretically).
Thank you.
triac power dissipation
Hi,
I've got a question about a triac dissipated power in full-wave conduction.
Why is it equal to :
V_0 (triac knee voltage) x I_AVE (mean current) + R_S (triac slope resistance) x (I_RMS)^2 ?
What is the meaning of these two values?
Thank you.
op amp can input exceed supply voltage
I know that there are diodes in microcontrollers for example but is it the same for op-amp? In the datasheet of ua741
https://www.ortodoxism.ro/datasheets/texasinstruments/ua741.pdf
it is said that "The magnitude of the input voltage must never exceed the...
amp max input
Hi,
For the majority of OP-Amp, the maximum input voltage is equals to the power supply voltage. What happens if the input signal is different of 0 while the OP-Amp power supply equals 0?
Thanks a lot.
The signal has a low frequency. If the signal doesn't change during some times, I will lose informations if I use a decoupling capacitor?
How can I choose the value of the decoupling capacitors?
Hello,
I have an analog output PLC module that is single ended : analog out and analog ground. I want to use this signal to control a differential analog input from a servodrive : analog+ analog- and analog gnd. How can I wire this with a twisted shielded cable in order to minimize the EMC...
current loop in velocity loop
Hi,
I wonder what is the utility of the velocity and current loop in a servomotor drive when the servomotor is position controlled?
By the way, with the position control, is it possible to control the speed and acceleration of the servomotor since speed is the...
Hello,
Do you have any articles or links about the DC motor position control with multiple closed loops. I mean using a position sensor (encoder) then computing the position error (desired position - real position), then we know that the motor does have to go at the desired position in a time T...
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