Questions tagged [component-selection]

All related to methods to select the correct components and/or component values to specific applications

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156
votes
6answers
20k views

What is the reason that the value “47” is so popular in electrical engineering?

We often see component values of 4.7K Ohm, 470uF, or 0.47uH. For example, digikey has millions of 4.7uF ceramic capacitors, and not a single 4.8uF or 4.6uF and only 1 listed for 4.5uF (specialty ...
12
votes
3answers
13k views

How to choose a inductor for a buck regulator circuit?

I am designing a buck-regulator circuit, with possibly the MAX16974 as the regulator. I have never done such a thing before, and actually not too much analog electronics at all. I got stuck at the ...
10
votes
6answers
4k views

Sensor for ultralow (to -85°C) freezer monitor

I am planning to build a series of Arduino-controlled temperature-reporting units for a room full of "Ultracold" -80°C freezers. (I ultimately want to convert the signal to a serial stream that will ...
22
votes
6answers
2k views

How do I plan a long range product with microcontroller that needs long term support?

I need to use a microcontroller on a system that must stay working without major changes for a long time (decades). To ensure that there always will be replacement parts, I need a microcontroller that ...
21
votes
5answers
94k views

What is the difference between 1N4001 and 1N4007 other than their maximum reverse voltage?

I compared 1N400x diodes here. As far as I see, all of their properties are same other than their maximum reverse voltages. Their maximum current recovery time reverse leakage current capacitance ...
7
votes
1answer
1k views

Using the VO2223A to switch a 230Vac LED lamp

I'm looking for something that can switch on and off a 230 Vac, 26mA LED lamp, under microcontroller control. Would a VO2223A, driven by (say) a PIC or Arduino, work as a low-current SSR? The load ...
10
votes
4answers
659 views

Resistor selection for LED

This isn't asking the equation to determine the necessary resistor for LEDs, but more asking the general practice for selecting them. I've seen multiple circuits that have used much higher resistor ...
6
votes
2answers
2k views

Choosing capacitors for Microwave RF application

I've recently been given a project to lay out some PCBs which will contain a few Mini-Circuits RF amplifiers, and their associated biasing components. However, since I need to have several stages of ...
9
votes
7answers
14k views

What PIC should I use? [closed]

What's the best PIC to start learning with? I want a PIC with 8 pins and with analog inputs. I have an 16F628A, but I think that the 16F684 could be better. What is the difference between PIC16F648 ...
5
votes
2answers
3k views

Inductor selection for obtaining a noiseless analog power rail

I interface an image sensor, and the design schematic for power supply is: How do I choose one from the available 3uH inductors based on the specs? I figured the maximum current and dc resistance ...
10
votes
5answers
1k views

What's cheaper & faster for my lab, keep a stock of electronics components or order? [closed]

We are four electronic engineers working in a company, and we have a lab, I think we have a logistic issue with our components, this might be a basic study case: We have few racks with resistors, ...
3
votes
1answer
996 views

Is there any science (or trick) to determining a replacement op amp?

I have a "mature" circuit design that calls for an LF411 op amp. I've built it up with a through-hole PDIP and it works just fine. Now I'm designing an SMD PCB for the circuit so I have the ...
15
votes
4answers
10k views

Ceramic (MLCC) versus Tantalum capacitors

From the perspective of an electronics designer, but also taking into account price/cost and social considerations (see Coltan mining and ethics link below), I tend to avoid Tantalum capacitors under ...
7
votes
3answers
26k views

What's the difference between linear and audio tapers, and why should I care?

I'm stocking up on a variety of potentiometers to keep on hand for my audio projects, and I'm trying to figure out what to buy. The projects I'm working on seen to call for either linear & audio ...
5
votes
1answer
6k views

Selecting capacitor for voltage-divider of half-bridge high power SMPS

How to dimension the capacitor for the voltage-divider of a half-bridge high power (>5KW) SMPS power supply? The question is more on type of capacitor and current rating than the capacitance. I have ...
1
vote
2answers
217 views

Signal path switching for effect circuits

I'm trying to build a method of switching signal order with three circuits in a rack unit. I've been researching different methods, using relays, using CMOS etc but I'm getting a bit overwhelmed and ...
0
votes
2answers
3k views

Would the FCA47N60F work for a ZVS flyback driver?

I have built a few flyback drivers from 555 controlled to the ZVS. I always have one problem, the power transistors keep burning out. For the ZVS driver, I used the IRFP250 and keep having the problem ...
7
votes
2answers
3k views

Pre-biased Bipolar Transistor (BJT) Tradeoffs

If you go to the Discrete Semiconductor category on Mouser.com, there is a section for "Bipolar Transistors - Pre-Biased". Is this as simple as including a resistor in series with the base? Are there ...
5
votes
1answer
3k views

What kind of knob fits a slotted potentiometer shaft?

What I thought was an easy question is more elusive than I suspected. I have a number of potentiometers that have smooth (not knurled) shafts with a slot cut into the end...it looks like a flathead ...
3
votes
1answer
126 views

Difference footprints of part in Altium Designer

What is the numerical difference between footprints marked with "* _M", "* _N", "* _V" and "* _L"? P.S. I was looking any information in google, but as a result nothing.
2
votes
2answers
4k views

LTSpice - How to specify the component model name through .param directive

I have some subcircuits that I want to define as components, but still be able to specify the component models used internally, for a much quicker testing of the design's performance under different ...
2
votes
1answer
68 views

Sourcing Transformer with Specific Turns Ratio

I am looking at a building an electronics project that calls for a transformer with a specific turns ratio '1:4:50', and am trying to source a component. I am working on the project from this tutorial:...
1
vote
1answer
74 views

Suitable Replacement for a Dual Coil Latching Relay

After questioning about my broken thermostat there Debugging an old Thermostat: What component is this? (3 pins SMD IC), thanks to @JRE I could find that it was actually the relay on the board that ...
1
vote
2answers
597 views

How to select a proper transistor?

I've got a schematic that calls for an unspecified "NPN Negistor". From my understanding of the circuit, the NPN is an oscillator that generates two audio tones for testing. Here's the schematic: I'...
1
vote
2answers
518 views

Mechanical Switch in parallel to the Micro Controller working in Sync

Here is the image for my requirement,want to operate Load Lamp of 230V AC with Mechanical Switch in parallel to Controller where one can 'ON' the Load Lamp from the Mechanical Switch and 'OFF' from ...
0
votes
3answers
354 views

Best way to get components for a new electronics lab [closed]

I recently joined a lab that is still in the process of getting set up. Our approach to acquiring electrical components (e.g. resistors, caps, opamps, etc.) so far has been to just wait until we ...
0
votes
1answer
362 views

Differences between 220pf 1000V capacitors

I need to replace a popped capacitor. Externally, it looks almost like (source) except for the first letter: in my case it is R and not ...
0
votes
2answers
143 views

Where can I search components according characteristics, not model?

I'm 2 years disconnected of electronics, and i don't know how i get and know the components i used, and i want to get and know few more components, but i can't get to know them... and well i was ...
0
votes
3answers
427 views

LED Resistor Choice with changing voltage

I'm planning on adding leds to a small quadcopter which runs on a 1s lipo battery. I am planning on attaching the leds straight to the battery rather than the regulated voltage the main circuit board ...
-1
votes
2answers
102 views

Arduino - component selection for controlling high-powered solenoids

I’m trying to replicate the circuit in the below diagram with a solenoid drawing 1.85A at 36V. First question: I think the TIP120 transistor should be fine, as it can handle switching up to 60V ...