Posts by Olin Lathrop
It's not completely clear, but it seems you are asking about a circuit in a class 1 div 2 location that will drive another circuit in a class 1 div 1 location. The point of the IS barrier is to pre...
No, I have not seen this circuit before, and don't know what source you may have gotten it from. However, I'm not sure that really matters. I don't know what exactly you are trying to teach, but m...
Currently, we have two categories, Q&A and Meta. Those seem to be working well. New topic type available A category can now be created where there is a single post per topic, with only comment...
First, draw schematics properly when you ask others to look at them. Your right to left flow is rather annoying. There are two main possibilities for this circuit to cause noise, the inductor and ...
It doesn't quite work that way. You are missing the fact that the current (which the magnetic field is proportional to) decays exponentially. You are also missing the resistance of the coil itsel...
RTOS A RTOS (Real Time Operating System) is much more than a bunch of interrupts. Most true dedicated microcontroller applications don't need any RTOS or any other kind of operating system. Genera...
Bootloader definition A bootloader is a program that runs in the microcontroller to be programmed. It receives new program information externally via some communication means, like a serial port, ...
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...
As an alternative to doing the math, as detailed in Andy's answer, you can use a graphical aid called a Smith chart: These were used routinely before computers to match transmitters to antennas. ...
Pi filters are often used to block high frequencies between a device and the power line it draws power from. In such applications, the considerations specifying the inductor include: How much powe...
First let's define what a "Pi filter" is: The name comes from the inductor and two caps forming the shape of the Greek letter Π. These filters are used for EMC compliance because they attenuate hi...
The days of socketed microcontrollers are long gone. In most cases, the socket would cost more than the micro. Nowadays, microcontrollers, whether in quad flat pack packages or not, are surface mo...
The short phrase is trying to capture the two broad classes of topics here: Electronic things, like opamps, transistors, microcontrollers, 20 W power supplies, and the like. Utility-scale power sys...
You can't eliminate all noise, use no memory, no processing cycles, and not add some lag. However, you can do much better than a brute force "moving average" filter. FIR versus IIR filters There a...
My control system gets a signal representing the plant output, but that signal has a lot of noise on it. The control system goes nuts trying to react to the noise. I need to filter out the noise ...
I recommend using native HTML for lists, and most other formatting for that matter. HTML gets around the ambiguity of what is an item and what is text following the list. The list isn't over unti...
First, let's redraw the circuit a little more clearly, with logical flow left to right. This also protects the answer from possible changes to the question. As you say, Q1 is a switch to control ...
To understand this issue, we have to look at how your circuit works and what the pullup does within it. You have a pushbutton you want to read with a microcontroller. The pushbutton is a momentary...
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...
The reason the transistor is dying is because you didn't put a flyback diode across the relay coil. Relay coils have significant inductance. This means the current can't change instantly without t...
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, ...
Voltage Rating If a device says it needs a particular voltage, then you have to assume it needs that voltage. Both lower and higher could be bad. When no tolerance or input voltage range is specif...
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...
Are we ready to let the world know about this site yet? What, if anything, do we still need to do or set up first? I have created a bunch of help pages that are intended to give newcomers a good i...
