Questions tagged [level]

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1 vote
2 answers
670 views

Are those electric fields dangerous?

Is 8.6 amperes per meter, 70 microtesla, 0.70 gauss, 695 milligauss, safe on long time exposure? I am just worried.
1 vote
1 answer
48 views

Control R channel volume from L channel

I have a mono line level (signal and GND) and I want to create L and R channel from it (to output sound to 2 separate speaker) BUT I want to be able to control the volume of the R channel.   Creating ...
3 votes
1 answer
96 views

Get resistor values for voltage divider/attenuator

I have a 10 V audio source that I want to bring to line level: 1 V. That's pretty easy: I just need to use a voltage attenuator, 10:1, like in the image below. I used resistor values of 1 k\$\Omega\$ (...
0 votes
3 answers
171 views

Using the same power supply produces no sound [closed]

AS SOME OF YOU ASKED, here is the video showing the connection and the problem: https://photos.app.goo.gl/GRsxQ783Rec6jVxo6 One clue that I got today: the problem happens EVEN if I disconnect the ...
3 votes
1 answer
177 views

Water level indicator LED lights up even though circuit is open

I have built a water level indicator with a 555 timer. The supply is a 12 V SMPS adapter, the output of 555 timer is a square wave with a 21 kHz frequency. I pass this signal into AC coupling to ...
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0 votes
1 answer
105 views

Humming sound when not touching wire

I explained this problem in a video so you can see with your own eyes the problem... touching the GND wire makes the problem go away, however touching the signal wire creates the problem. Even ...
0 votes
2 answers
100 views

Convert speaker level to microphone level

I have a digital piano without line output (not even earphone output) but I would like to record what I am playing. So I decided to convert the speaker level to mic level so I can record the audio in ...
2 votes
2 answers
423 views

Line level to microphone level to record

I have a digital piano with an earphone output where I can connect a simple earphone (like in the picture below.) It works fine. I would like to connect this earphone output to my smartphone jack (...
0 votes
3 answers
142 views

Voltage divider from speaker to line level generates noise/huming

I have a really old device and I can only access the speaker wires of it. I want to setup a line level from the speaker so I can connect it to another device. I used a very simple voltage divider (2 ...
0 votes
2 answers
139 views

Water level indicator using transistors

I'm trying to designing a water level indicator using npn transistor(BC548). I tried simulating the circuit on PSpice, but I don't know what to add for the sensor. I want a graph. The circuit will ...
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0 votes
1 answer
73 views

How to score glass to shine straight horizontal laser line through [closed]

I’m trying to make a DIY laser level, I took apart a cheap one to see how to shape a laser spot into straight lines, it turns out that a simple laser beam passes through a small piece of glass (or ...
0 votes
1 answer
52 views

The reason behind LEDS getting dim (Water level indicator using ULN 2003) [closed]

** Whenever I switch on the circuit, the LEDs glow fully for a second and gets off. After 2-3 seconds they start glowing slowly. What might be the reason for the above?
2 votes
1 answer
52 views

Picking a FET for Logic Level

I've always been confused when picking a FET to be used for logic level signals. There are so many factors to look at for FETs, I get overwhelmed. In this case my supply voltage will be a 3 alkaline ...
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-1 votes
1 answer
370 views

What are the voltage levels in 100 Base-TX Ethernet?

I know what the differential voltage looks like. If you measure across Tx+ and Tx- it goes from -1V to 0V to 1V and so on, but how are these voltage levels actually transmitted? Does Tx+ go from 0V - ...
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2 votes
2 answers
245 views

Simplest way to check if an audio level is line or micro?

I can check level audio on a VU Meter or dBFS meter. What's the simplest way to check if an input audio level is line or micro? Can I use a multimeter?
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0 votes
1 answer
59 views

lowering output level of a phono preamp

I built a RIAA phono preamp that works great from these schematics: But the output level seems a bit too high. What would be the best way to lower it?
  • 121
1 vote
0 answers
377 views

Sound level meter using a microphone with ADC

I'm working with STM32F4, MAX4466 amplifier and a condenser microphone. In other words, Adafruit 1063. I want to get the sound level in dB unit. I know: Microphone sensitivity: 0.0063096 V/Pa ...
0 votes
0 answers
144 views

Level shifter problem

I have a question regarding a level shifter schematic that I've implemented. I need to connect a 1v8 logic UART device to both an arduino and a TTL232-3V3 cable. The Tx side works as expected and I ...
0 votes
0 answers
92 views

Level sensor Transmitter

I have a level sensor and transmitter(4-20mA standard) of Qidian Automation for sensing level of liquid in tank having capacity of 1000 litres. On transmitter it is displayed 0.516 when tank is half ...
2 votes
0 answers
65 views

Strange levels on UART TX

I am trying to get the boot chatter from a UART on IOT device. When powered up TX line goes high as expected (3.3V), but when it starts "talking" - scope shows that hi/lo levels swings are ...
1 vote
3 answers
256 views

Conceptual Question regarding necessity to do level shifting

I have a circuit where a 3.3V MCU which is not 5V compatible needs to drive an MCP23017. The MCP23017 will drive and read inputs and outputs from various 74HCT components. I'm thinking that based on ...
1 vote
2 answers
2k views

How to control one motor with two float switches

I have 2 tanks , one is under another and hopes to pump from under tank to upper one using a 0.5 Hp single phase motor.By connecting float switches for both tank,can I control the motor to turn on ...
1 vote
1 answer
790 views

Does the MPU9250 require a 5<->3V3 level shifter when used with Arduino Uno?

this is a quick question. I'm building a flight tracker which uses several breakout boards. Most of which operate a 3V3, hence they require level shifters to be able to work with the Arduino without ...
1 vote
1 answer
197 views

Audio line level conversion from consumer to unbalanced (presumably) pro 1/4" jack of unknown sensitivity and impedance. 400W 1980s PA amp

I have a lovely pair of speakers that achieve their almost flat response by dampening spikes. Consequently they eat amp power for breakfast. I have been given a 400W RMS per channel 19" rack mount ...
0 votes
1 answer
107 views

Voltage level shifter using opamp

I am making a circuit to acquire EOG signals and read it via the analog pin of Arduino. The arduino reads only positive signals, which is why I am unable to see the negative spikes in voltages caused ...
1 vote
1 answer
95 views

Need help in understanding the working of battery level indicator

I have got hold of a battery level indicator on net. I works but I am not able to understand how it is functioning. I am new to electronics and I just dont want to build a circuit from a diagram. I ...
0 votes
3 answers
134 views

Water level sensor. How to read it?

I have a water level sensor in which by varying the level of the water, an inductance change his value in a mobile coil. The sensor have the internal simple schematic like this (i don't know the value ...
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2 votes
2 answers
1k views

RS485 transceiver supplied with 3.3V. What voltages can I receive?

I'm designing a print for RS485 with the LTC2854 transceiver, but I don't know in what exact situation it will be placed in. So I don't know what voltage levels the other devices will communicate on. ...
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1 vote
2 answers
744 views

Colpitts / Clapp oscillator crystal drive level

simulate this circuit – Schematic created using CircuitLab As I understand this circuit has some initial gain at startup, then as the oscillation builds up gain goes to unity at some moment. ...
  • 69
0 votes
1 answer
188 views

FT232R TTL Logic Levels

I have an FT232R chip hooked up to my oscilloscope with the TX and RX pins joined. I'm sending characters directly to it via Putty. The logic levels I am seeing are 5V low and 0V high. I thought the ...
  • 119
2 votes
1 answer
332 views

Why do we ground the common probe on a 3 probe liquid level sensor?

I have a liquid level sensor with 3 probes, one us common, the other is for low level and the third is for high level. On the liquid level control relay diagram, I've noticed that the common probe ...
  • 317
-1 votes
1 answer
126 views

Level Matching Circuit

Somebody know what do this circuit exactly or how it works ? Where VDD = 5V (MCU) and VDD_1V8 = 1V8 It is a recommended circuit to use uart communication when the voltage level are not the same, I ...
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3 votes
2 answers
3k views

What is the common name for this seal-in relay?

I'm trying to build a hysteresis water pump system with 2 water level switches. Please see the diagram and explanation of this setup I've taken off the web: The first switch (L) is set at the minimum ...
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0 votes
1 answer
629 views

How to make a battery level indicator for arduino (The battery is powering the arduino also) [duplicate]

Hi I am building a pocket altitude, temperature and humidity meter with 1.8" TFT display. I have a 1000mah 3.3v Li-ion battery to power the whole system. I also need to display the battery level in ...
1 vote
3 answers
418 views

Sensor For Continuous Water Level Measurement

I am designing water level controller for water tank and want to show the water level in LED bar Graph I know how to transmit data to MCU and show level to LED bar graph but my problem is to find ...
0 votes
2 answers
247 views

4-Channel Level Converter outputs voltage when it shouldn't?

I am converting 5V to 3.3V (for a rudimentary Raspberry Pi project). The level converter scenario below behaves as I would expect: Because HV1 is connected to 5V, the voltmeter connected to LV1 and ...
  • 3
2 votes
1 answer
952 views

PCM5102A: analog output level not what I expected?

I cannot achieve a 2.1 Vrms mentioned in their datasheet (pages 4 and 9). I can only output 1.04Vrms from the 1kHz source. Do I measure it wrong or this is what I should expect? Or maybe I get such ...
1 vote
2 answers
866 views

Tank Water Level Indicator Wire

I am building a simple water level indicator (approx like the circuit below) for my tank. However, I am wondering about the wiring, for I suppose copper cables corrode in water and produce toxic ...
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3 votes
1 answer
127 views

Point Water Level sensor

The company I work for uses conductive point-level water sensors to determine water level in a small tank. The manufacturer of these sensors has proven to have very unreliable quality control and ~30% ...
0 votes
1 answer
53 views

Automatic level shifting

I have a signal which can have a different offset voltage based on the requirements. However, I need the voltage to start at zero. Since the offset is variable, I was hoping if there are any ...
  • 922
1 vote
2 answers
106 views

sn74lvc1t45 pullup on the DIR line

The part sn74lvc1t45 we are sing as an SPI translator. We usually use B -> A which means DIR goes to ground, however in a new design we are reversing this, and as a result, as per the DS it (being ...
2 votes
1 answer
751 views

Can anybody help me modifying a reverb circuit on a guitar amp to an FX loop circuit?

I have a solid state guitar amplifier with a reverb tank. I have done a bit of research as to how these work. I now want to replace the reverb tank with an FX loop for normal pedals (instrument level)....
1 vote
1 answer
463 views

How does this USART level shifter circuit work?

I'd like to ask how this circuit works: I understand how it works in principle, but not technically. It's a USART voltage level shifter. It's supposed to divide 5V to 3.3V by a resistor divider, in ...
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5 votes
5 answers
1k views

Will this water level indicator circuit work for my project?

I have only rudimentary knowledge of electronics so I ask for your forbearance. There are many water level indicator circuits, of the type shown below, listed online and demonstrated on YouTube. The ...
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1 vote
2 answers
951 views

Selecting a logic level MOSFET compatible with 3.7V power source

Continuation of prior question: Logic level mosfet to switch on 3.7v battery I am a 'mature' entrepeneur Arduino level electronics noob, apologies. Want to build a flashing alert using 3W LEDs in ...
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2 votes
0 answers
70 views

Need a simple buzzer/LED circuit for espresso machine [duplicate]

I have an espresso machine that I tore down, reassembled with fewer components then modified it to fit a specific setup -- kind of DIY project. The machine has an autofill circuit. After I removed ...
1 vote
0 answers
515 views

RS-232 Level Shifter

Most PCs don't have RS232 built-in anymore. So the only option is USB-2-RS232 adapters or RS232 PCI-E card. While I expected the adapters to output a low voltage it turns out most RS232 PCI-E card ...
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0 votes
1 answer
123 views

Level Conversion RGB LED Strip Noise Resistor (3.3 to 5)

I recently prototyped my circuit on a breadboard that controls a WS2812b RGB LED Strip. The PDIP (breadboard friendly) ATMEGA644 uses 5V logic while TQFP uses 3.3V logic. The LED strip specifies a ...
1 vote
1 answer
2k views

Water level indicator with PNP transistor

I wanted to create a circuit that Lit's up an LED when water level rises to a certain level. I have created the following schematics following the https://www.electronicshub.org/water-level-alarm-...
0 votes
1 answer
699 views

Capacitor in RS232 level shifter. Data is strictly half-duplex

I have created a level shifter very similar to the schematic at: http://picprojects.org.uk/projects/simpleSIO/ssio.htm except for the capacitor I use 47nF because the page claims: at high bit rates ...
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