Questions tagged [schematics]

The diagram that shows how the parts are hooked up logically. If your question is about a specific schematic software package, use that tag instead.

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1answer
54 views

Window comparator diode direction

What happens if we reverse the configuration of diode in window comparator? Will it remain a window comparator?
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2answers
36 views

Voltage divider in parallel with DC motor driven by H-Bridge: can someone explain me this circuit?

I have a battery powered device with a PCB wich control a small DC motor (3V). With a little bit of "reverse engineering" I darw this schematic: So there's an 8-bit IC (STM8L052C6) that drive the ...
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1answer
40 views

Touch IC TTP223 is hanged at 5V after some times work

I used TTP223 IC which is operated at 5V , i use touch ic output(When High)to turn on the led and (When low) to dim the led. LED is operated by the External 5V and used only touch ic output as signal ,...
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3answers
6k views

What does the “capacitor into resistance” symbol mean?

I can't understand the circled symbol and didn't manage to google it. It looks like a variable resistance and a capacitor. What does it mean?
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1answer
29 views

Is this circuit for Piezo Transducer and corresponding resistor values correct?

I want to drive this piezo transducer (https://www.mouser.com/datasheet/2/670/cpt-9019s-smt-1310960.pdf) at 3V and 4kHz with STM32F0 microcontroller. This is a follow-up to my previous question (Is ...
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63 views

KiCad Saying Pins Not-connected

So I am fairly new to using KiCad, and I have encountered a problem. I recently learned how to make hierarchical pins for bus assignments with the notation. ...
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1answer
99 views

I need help to understand a sniffer circuit schematic

I'm an electrical engineering students and for a school project I need to understand a circuit schematic. First, I will provide some context. The school project I'm working on is the modification of a ...
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0answers
56 views

Is there a standardized symbol/refdes for PCB mounting points?

I've seen a variety of different parts substituted in for mounting locations, including 1-pin header, test pad, and fiducial symbols. I've also seen a variety of reference designators for mounting ...
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1answer
54 views

junction points on schematics

Website for the wiring In the schematics circled orange and purple I see a transistor to what I think is connected to a black wire and black and red wires connected to each other. Are these junction ...
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0answers
25 views

OrCAD CIP CIS Part number

I have added some parts using CIP function in OrCAD and they can be added in Schematics as well. Problem is when i look at part manager window of that schematics, those parts have not been assigned ...
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0answers
31 views

Circuit breaker wiring: put source current on side marked with X or side with switch? [duplicate]

I am trying to wire an electrical panel in a standard manner. I have several automation devices that take 120 Vac power. In order to protect them, I have purchased a 2-pole circuit breaker, Phoenix ...
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0answers
26 views

How to use ESP-WROOM-32 to send wireless TX and RX commands from a PIC?

I want to have the possibility to send the commands of a PIC in a way that it's wireless and I thought it would be a good idea to use a ESP WROOM 32. In the datasheet it has the following schematic: ...
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1answer
43 views

Altium: How to place the pin name inside rectangle in schematic library

How can I make the pin name to be adjacent to the "Active X" mark on the pin? In earlier version of Altium it was default. Here V.17. In V.19 it is the opposite. In order to make the name go inside ...
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2answers
67 views

MXR Distortion + guitar pedal schematic - meaning of +4.5V

I found this schematic of the "MXR Distortion +" guitar pedal. I am trying to rebuild it, but I have some doubts about this +4.5V in the bottom left corner. What does it mean? I mean, I have only 1 ...
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0answers
38 views

How can I connect a Peltier Element?

I need help to anyone who can help me 🙂 A peltier can be reversed. So If I supply + to RED and - to BLACK it works as expected. But if I reverse the polarity, ( - to RED, + to BLACK), it will also ...
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1answer
93 views

Unkown symbol in schematic

I researched but I could not find anything like this, should I be worried about what is this symbol? This schematic is a part of a board I'm working on, the part that regulates voltage from 2.6 - 4.2 ...
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1answer
87 views

What is this schematic symbol? A transformer?

I found this schematic symbol I've never seen before. I think it's some type of transformer? Please let me know what it is.
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1answer
52 views

Power supply design, Pi filter

I am designing a power supply circuit. Does anyone have any calculation formulas for resistor which we connect across inductor or capacitor? I have attached a circuit with highlighting a connections ...
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1answer
47 views

Arduino AREF pin

In Arduino UNO R3 official schematic the AREF pin is not connected to anything: While in most online Arduino schematics (such as this one) it's connected to a 100nf capacitor and then to the ground, ...
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0answers
51 views

Voltages at nodes in TTL logic gate

I'm trying to answer the question that has been given here. I think I understand which transistors are on and which are not under the two different logic states i and ii. However, what I really ...
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3answers
336 views

Strange-looking FM transmitter circuit

I found this simple FM transmitter circuit: I built it an it works rather nicely. There are many simple FM transmitter circuits on Google, most of which look basically like this: These work by ...
35
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2answers
6k views

What is this symbol: semicircles facing each other?

What does this symbol represent? It was found on the circuit diagram for a TDS973A a board for which this was the only information I was able to find online.
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0answers
35 views

Numbered rippers versus names in schematic capture

Long-time Altium guy here that just came onto a team that uses Mentor DxDesginer. When I first came onto the team, several people warned me to be careful with rippers, because they can inadvertently ...
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1answer
59 views

Advice on battery powered ESP32 with NFC Design

I'm new to PCB design (First one) and I want some advice and tips from more knowledgeable people in regard to basic design elements and especially the power consumption part. I want to make the ...
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1answer
36 views

STM32F103RCT6 custom design check

With little experience with electronics and comming from an Arduino background I am designing my first STM32 PCB. My question here is, since this is my first attempt, I would like to have some advice ...
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1answer
65 views

PAM8009 help understanding schematic

it's the first time I encounter this in a schematic, and I'm wondering at how to reproduce this in Eagle. So first number 1. As per description, the volume pin is "Internal Gain Setting Input Connect ...
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2answers
10k views

Weird resistor with dots around it on the schematic

I was looking through the LTC4041 datasheet and saw this: The 10mOhm resistor with the two nodes really close to it - is that a "special" resistor or something? Why have they drawn it like that?
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1answer
70 views

Arduino Mega Schematic possible “Faults”? [closed]

I'm trying to build an standalone Arduino mega based on This schematic. At the header of schematic Arduino noted this: Reference designs ARE PROVIDED "AS IS" AND "WITH ALL FAULTS". As a hobbyist ...
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2answers
88 views

Electrical schematic symbol help(looks like an or gate)

I'm wondering if that little dot represents anything?
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2answers
65 views

Why my Battery Protection + Charging + Buck/Boost design doesn't work

Disclaimer: I am a total beginner in electronics, no professional degree whatsoever. I have designed the below 1 cell Li-ion battery protection/charging/buck-boost circuit and I've also designed the ...
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1answer
55 views

How should I use 3.3V + 5V in KiCad without getting an ERC error?

Below are parts of my design. Using KiCad, I have problems using both VCC (5V) and 3.3V power, both from Arduino Mega pins. If on U6 (flash) I connect 3 and 7 I get a similar error, so I guess I did ...
21
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1answer
2k views

Capacitors with a “/” on schematic

I'm looking at a schematic for an old turntable that I am needing help on when viewing the capacitor values. All of the polarized caps will have 2 values written next to symbol i.e. ...
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2answers
171 views

What is the point of these components on the schematic? (Digispark ATtiny85)

The above schematic is for the Digispark ATtiny85 development board. I am still fairly new to electronics, however I understand what all these components' functions are. I am just not sure why it is ...
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1answer
102 views

68008 Main board Review [closed]

I'm building a retro computer around the 68008 CPU The main board will be simple, The CPU, 1MB of RAM, and a 32kB ROM (Bios/boot rom) here is the adress map $000000 - $07FFFF : RAM0 $080000 - $...
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1answer
51 views

How to read this switch data

I'm come across a schematic that uses a switch symbol shown below. This switch is a Kraus & Naimer CA10 Switch (That's all I know). The schematic symbol is shown on the right with terminals ...
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0answers
61 views

Thurlby PL310 bench power supply: what does these resistors do?

I have an issue with my PSU showing 'ofl' on its voltmeter, despite the output working fine. Could you explain to me what the resistors in the red box are for and why it needs them?
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2answers
89 views

What is the purpose of the optocoupler in this circuit to drive the mosfet/relay?

I'm currently trying to understand a circuit for an ESP8266 relay board. As you can see in the schematics below, an optocoupler is used to drive the relay mosfet. I do not understand, why they are ...
3
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1answer
171 views

What is this schematic symbol? Transistor ? Variable Inductor

I was looking through an old schematic and found two symbols that I didn't recognize: Is this a PNP transistor? looking up the model number doesn't give much information. Is this some kind of ...
3
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1answer
105 views

What is this connector symbol?

I'm working on a PCB design homework in PADS and I've come across a symbol that I have never seen (circled in red below). It is of a filled in rectangle with a triangle below it. I'm thinking it ...
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1answer
145 views

Help identify IC with erased label by using pin connections in the schematic

I am reversing a board which some of its IC labels are erased by the manufacturer. I've drowned its schematic in the picture below. The label-removed ICs in the schematic are IC5, IC8, and IC13 which ...
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0answers
175 views

Please check my board design before I waste money

TL;DR: Please make sure my schematic and board design won't blow up on me. GitHub Repo if you're feeling extra thorough. Project overview I am trying to create an Arduino based Bluetooth RGB led ...
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2answers
471 views

What is the meaning of “do not populate test points” in a board schematic

I was finding test points in a schematic of an Analog Devices Evaluation board. In one of the schematic pages, there is a clause mentioned "do not populate test points". Does anyone knows what it ...
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1answer
52 views

What are the additional transistors used for in this hex inverter?

I'm learning about electronics and was studying the SN7404 hex inverter schematic when I saw this: I naively expected just a single transistor (the one in the bottom right) and the input at the base ...
1
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1answer
39 views

Baxandall tone circuit passes signal through but does not alter its tone

I added an Baxandall active tone circuit to an existing overdrive circuit and I'm having an issue. The signal passes through the circuit/opamp and out to my volume control but the bass and treble ...
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0answers
34 views

Pin confirmation on pic for sd card connector?

I've had a first version of a connection to a sd card connector (DM3CS-SF) for my PIC32MX470F512L that did the following connections: After trying to run an harmony example, using this config, the sd ...
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1answer
76 views

What could be the reason these wires need to be connected outside of the sensor?

Below diagram shows the inner system of a wind-meter and four output wires to power it and collect the 4-20mA output signal as current or voltage by using a resistor. I verified with a voltmeter's ...
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1answer
94 views

Problem with boost converter

I am currently trying to use the LMR61428 boost converter IC with the configuration in the attached schematic and having an heating problem with the inductor. The inductor gets very hot very fast even ...
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1answer
104 views

What is this dumbbell looking symbol on this schematic? (looks like jumper pad, but with a short)

Regarding to SJ1 and SJ2 in this schematic: On the board it looks like two ordinary copper pads but with a thin connection between them. Is it meant to be a way to open the circuit by scraping off ...
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2answers
100 views

I need some help understanding the schematics of DIY HS102 oscilloscope

I was looking on the schematics for the DIY HS102 oscilloscope by Martin Loren (http://hscope.martinloren.com/HS102-oscilloscope.html) But I'm a bit confused about the role of the ASM1117 (LDO ...
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0answers
41 views

Guitar to iPhone JFET pre-amp circuit issue

I am following this tutorial to build a simple JFET pre-amp to connect a guitar to an iphone. This is the schematic: I have soldered the components as per the schematic directly onto the 1/4" mono ...