Questions tagged [component-selection]

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

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Inductor and Capacitor 3-digit exponent value codes: is there a standard?

I've seen the standard NNX exponential value code where NN are the significant digits and X ...
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2 answers
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Is there a type of transistor (or other semiconductor device) that can do this?

I haven't completely given up yet, on using some kind of semiconductor for the boxed ??? device below, to control an ATX power supply: simulate this circuit – Schematic created using CircuitLab ...
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What does EE10 or EE15 mean for transformer cores?

I have been studying about transformers. When I went to buy some transformer cores from Alibaba for research, I saw different names like EE 15 transformer. What does the EE10 or EE15 transformer code ...
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1 answer
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Trouble finding LDM for EMI filter

I am trying to use this DC-DC converter and I am having trouble recreating the recommended circuit as I'm not entirely sure what an LDM is or where to find one: From basic google searches it looks ...
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Type of transformer needed to measure 4-20mA process current?

I occasionally work with 4-20mA process signals and need to read the current value flowing through the wire. I now use a standard Fluke 17B+ and must disconnect the loop and add the meter in series ...
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How do I make sure the replacement switch for a device can handle the power demands?

My 10 year old (out of warranty which ends at 8 years) blender on off switch broke. The unit still runs great, I don't want to trash it. I just need to replace the switch. But I don't know what kind ...
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1 vote
1 answer
50 views

Choosing a replacement electret microphone

I'm trying to select a suitable replacement electret microphone for an analog (POTS) phone. The existing electret is completely unmarked so I don't know its part number or parameters. I'm not well ...
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-1 votes
1 answer
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Trouble using PNP as a switch

I simulated a circuit as shown below and it works as expected when the switch is closed or opened. I later change the 2n2907 to FMMT591A due to availability, continuous collector current and size. I ...
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DC-link capacitor selection for electric vehicle

I'm currently trying to build a model of a three-phase inverter to be used in electric vehicles. The selection of a film DC-link capacitor is mainly dependent on the allowed voltage ripple, which is ...
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2 votes
1 answer
74 views

In calculating the inductor for a boost converter, where does the power of the voltage source calculate in?

simulate this circuit – Schematic created using CircuitLab As I am using LTspice to develop different types of dc-dc boost converter topologies and wanted to define the best inductor to use when ...
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4 votes
1 answer
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Noob questions about my accelerometer (ADXL345) and Arduino components in general

I've just bought this accelerometer: https://www.amazon.co.uk/XTVTX-ADXL345-Digital-Acceleration-Gravity/dp/B09NRFDH5J/ref=cm_cr_arp_d_pl_foot_top?ie=UTF8 I've bought it to learn about accelerometers ...
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AC and DC in the same Circular Connector

I have a machine I am working on that has an AC wire at 0.7A @ 120VAC, a 36V DC wire and some DC signal wires from a control board which are connected to a microstep driver for a DC motor. I would ...
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How do you make a single falling edge pulse when a falling edge is detected?

im designing a circuit where when the switch is open, the 555 timer ic's output goes high but in real life, for the 555 timer to go back to a LOW state, the trigger pin needs to be higher than 1/3 Vcc ...
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1 vote
3 answers
78 views

How to select IC components by just footprint and low price for Pick-and-Place testing?

I am very familiar with the usual vendors for components, and how to select parts for a design, including package and footprints. However, I'm looking for an efficient way to track down 'throw-away&...
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Low-profile, panel-mount connectors

I'm working on a hobby project, a handwired ultra-low-profile computer keyboard with a 3D-printed case. The USB-C connector on my dev board is only 3mm tall, so it fits within the 4.5~5.0mm of ...
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2 votes
1 answer
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Component footprint symbol cross-reference / cheat sheet / appnote?

While shopping for components I've noticed different manufacturers / suppliers will use different names / codes for identical footprints, which can make it a chore to work out what will actually fit - ...
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Best way to "cut" a connection on a pcb [closed]

Imagine you have some traces on a PCB, that connect from point A to point B. I would like to have control over that connection. I want to be able to enable/disable the connection from a distance (...
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How can I produce a continuous sound of pressure 70 dB with randomized noise? [closed]

How can I achieve a sound system that can produce a continuous sound with randomized noise in the range 70-75 dB? I need that for conducting a medical experiment in which the doctor measures stress ...
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2 votes
1 answer
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How to catch signal in ESP8266 when someone rings (doorbell)

I'm actually a software developer and new to electronics and ESP8266 etc. I want to learn electronics and my first project would be to catch the signal within ESP8266 when someone rings / uses the ...
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1 vote
2 answers
125 views

Relay selection for 48V loads

I want to use a relay to remotely switch a 48VDC 1A load (3A peak on startup with capacitive load), however, nearly all relays I have looked at specify a 30VDC maximum contact voltage. When searching ...
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1 answer
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Determining component design age

Is there a way to see when a component was designed without opening every datasheet? I look at some TI LED driver parts first released 2007, revised 2016. Is that datasheet or component? Does it ...
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2 votes
1 answer
85 views

How to choose the right flexible cable for moving parts?

Is there a generally accepted guide to select a cable, which has to withstand certain bending stress? I am looking for something like this: ...
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1 vote
1 answer
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DS3231 Question

Can someone help me understand the differences between: "Adafruit DS3231 Precision RTC Breakout" and one of these generic breakout modules, "DS3231 AT24C32 IIC RTC Module"? Why I ...
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2 votes
1 answer
156 views

How to choose a common mode choke for ethernet?

I'm currently working on a design which contains gigabit ethernet. Due to some weird size constraints, I can't use a magjack or one of those transformer ICs, so I'm using discrete magnetics. I've ...
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2 answers
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Which (if any) capacitors should I choose for these DC/DC converters?

I’m trying to choose/work out if I need capacitors for the input and output of two DC/DC converters. The first converter is a Murata PAE-29/3-D48, powering this along a ~30cm cable, and a bike ...
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2 votes
2 answers
366 views

Normally open pushbutton that remains closed until fully released [closed]

Description of desired item I'm looking for a button component that is normally open, stays open while pushing it, closes when the maximum travel distance is reached, and then stays closed until fully ...
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6 votes
4 answers
1k views

In terms of costs of mass production: is it better to try to reduce resistances' tolerance or capacitors' tolerance?

So I am doing a small project of optimization of components tolerance to reduce the impact of circuit sensitivity to meet a project specification. Right now I am with 5% resistors and inductors and 3% ...
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1 vote
1 answer
61 views

Power ORing with power switch with reverse current prevention

Power ORing is usually done with diodes so that the power source with higher voltage is powering the load. Can these diodes be replaced by power switches such as SiP32508 that doesn't have output ...
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0 answers
46 views

Replacement DAC for MCP4922

I have designed a circuit for controlling a device in the lab, using a Microchip PIC32MX Microcontroller, connecting via SPI to a pair MCP4922 DAC, the output is then adjusted with an operational ...
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1 vote
1 answer
204 views

How do I stop buck converter voltage from dropping whenever current increases?

I built this buck converter circuit using the LM2596T-5 (5 V OUTPUT, 12 V INPUT) using the exact components mentioned in the datasheet's first page (schematic below), except for the diode. I used the ...
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1 vote
2 answers
393 views

Selection of MOSFET for flyback transformer switching circuit

I am working on a project that uses a transformer in flyback mode to create plasma arcing. It's based on a simple circuit that's available in a lot of DIY kits which uses a MOSFET to switch voltage on ...
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1 answer
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What is wrong/missing from the process subsystem? [closed]

My teacher told me to reconsider the process subsystem but I'm not sure what is really missing from it. background story: when a guy is standing on the porch, the LED lights up
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Convert a through-hole type circuit board to SMD type

I want to replace the through hole parts of the following circuit with SMD parts (control section.) This is an 80W FPC using L6562A. Is this a straightforward action or does it require further ...
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2 votes
2 answers
103 views

IC for ultra-low power switching

I've previously used complimentary pairs (eg DMC2990UDJ) to switch ICs on and off. I've attached a schematic which switches a potential divider for battery voltage monitor as an example. Where R7 and ...
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-1 votes
3 answers
331 views

What is a suitable equivalent to 2N5459 JFET? [closed]

I am attempting to build an audio limiter circuit which has a JFET as part of the BOM. This JFET is obsolete and no longer manufacturered. Can someone recommend an equivalent JFET or a way of ...
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0 votes
3 answers
756 views

For the capacitor specification "Ripple Current at Low Frequency" is a higher value better for a linear power supply?

I'm finding information that seems to be contradictory in various places, and I think people are talking about different ways of looking at the same spec. The specification that Digikey uses to search/...
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0 votes
1 answer
147 views

What DC motor is suitable to push and pull 60 kg load system with wheels?

I have a projector system with a PS4 and other electronic devices that I put on a small shelf cabinet with wheels. In normal status it will stay inside the space under my wardrobe. When I need to use ...
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1 answer
217 views

Is there any reason to use the LM317 in place of the better and more recent LM338?

This more recent version of the LM317 is fantastic, and while it happened some of my LM317s "fried" somehow, LM338s never betrayed me. Reading the datasheets, I don't find any advantage to ...
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-1 votes
1 answer
75 views

Choose a varistor for a broken PC PSU [closed]

My computer's PSU (Corsair RM 650X) has blown. I've searched a bit online and I have found that this is a common defect due to a low quality varistor put in those kind of PSUs before 2018. I know this ...
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10 votes
14 answers
5k views

Should I take Ohm's law for granted?

I have started recently on the study of electronics. One of the most basic statements that I learned about electricity is the relationship between the voltage and the current across a conductor. I did ...
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0 votes
2 answers
42 views

Smallest Footprint Source Only (No Sink) Buffer Solution [closed]

I'm currently in the process of designing a cable snake cable tester for recording studios that involves testing for connectivity between a large number of inputs. This involves using a ...
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3 votes
2 answers
371 views

Why do manufacturers specify typical values, not just maximum and minimum?

Why do manufacturers specify typical values? I am still going to have to design my circuit so that it can accept values within the maximum/minimum values. What is the probability of getting a "...
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0 votes
1 answer
116 views

is it OK to replace higher ampere TRIAC for a washing machine?

I have a 6 year old top load washing machine which requires a TRIAC replacement for wash motor. The actual TRIAC that came with factory PCB board is NXP BT138X-800 and the one I am looking to replace ...
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0 votes
2 answers
182 views

Swimming pool depth sensing

OBJECTIVE: A device that floats on the water's surface and measures the depth. If any changes occur in the depth, it sends a report to a remote receiver. MY RESEARCH: I have considered the following ...
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0 votes
1 answer
105 views

Choice of mosfet transistor for linear operation (voltage controlled dummy load / current source)

BACKGROUND I have built very simple dummy load to test thermal behavior of some switching power supply (5V 5A). Vbat is 8-9V from 6F22 battery. Resistors are oversized to reduce working temperature. ...
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0 votes
2 answers
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How do I make sure my part matches with the eagle part selected?

I need help matching the part I have with the eagle part. I'm using a RPX-1.0 data sheet pdf: https://www.mouser.com/datasheet/2/468/RPX_1_0-1903909.pdf It is a 3mm by 5mm qfn with 16 pins but it ...
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1 vote
1 answer
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Why do DC/DC switching controllers seem to favour the buck-boost topology over similar ones like Cuk, SEPIC and Zeta?

I am looking at various DC/DC converter topologies for a power system I am designing. The most suitable topology for me is one that can perform both step-up and step-down functions, so I am looking ...
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0 votes
1 answer
67 views

Are there smaller packages for Standard rcl (resistor, inductance, capacitor) than 0402mm

I need to miniaturize a PCB as much as possible. Are there packages available on mouser for standard components like resistors (100k) or inductance (Up to 30nH) or Cap (Up to 100pF)?
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0 votes
1 answer
228 views

How to read Diode Numbering System

How do I read diode numbers. I read that the numbering system for US diodes is the JEDEC system. But I don't think the JEDEC system applies to diode numbers after 1N. Everywhere I look I cant only ...
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2 votes
1 answer
202 views

Step up 3.3V to 5V to use as power of op-amp

In my previous question I was thinking about how can I "reuse" this circuit (0-10V, 0-20mA and digital contact input), when I only have 3.3V regulated power available from my LoRa Node: ...
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