Questions tagged [trigger]

A type of oscilloscope sweep in which a *trigger*, or waveform characteristics matching a user-specified condition, will initiate the sweep. A trigger can also be an event, such as a pulse, which causes a circuit to begin performing some action.

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35
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4answers
117k views

What does edge triggered and level triggered mean?

I am studying 8085 microprocessor architecture and the word edge triggered and level triggered confusing me really very much. Can anyone explain me it in layman's words ? While studying the ...
17
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5answers
28k views

Why edge triggering is preferred over level triggering?

I am trying to understand why edge triggering is preferred over level triggering. In my book it is not explained clearly. After searching online I came to know that edge triggering is insensitive to ...
11
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3answers
3k views

What is oscilloscope trigger “sensitivity”?

I'm learning more about digital oscilloscopes (previously have only worked on analog), and encountered a setting for trigger sensitivity, expressed as a value like ...
10
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4answers
854 views

Why does my waveform start ahead of the trigger?

I am learning how to analyze SPI bus clock and data using an entry-level digital storage oscilloscope. I'm using a BK Precision 2542B to measure the output of the clock and MOSI lines from a Netduino ...
6
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1answer
727 views

Capacitive touchscreen [duplicate]

I am doing project in which I want to perform read and write operation by using a capacitive touchscreen. What I know is I can trigger capacitive touch screen by: By using electromagnet as I heard ...
5
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2answers
1k views

What is the difference between the circuits?

I found the trigger (latch) circuit: When no button is pressed, the LED does not light, if you press SW1, the LED will light up, and will light until you press SW2. This can work for different values ...
5
votes
4answers
918 views

Which edge is better for choosing a trigger?

I have a 100Hz signal with a fast rising time and slower falling time. This is the output from a zero crossing detector. The signal is connect to an Arduino input pin. Arduino can generate an ...
5
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4answers
7k views

trigger alarm with relay from PC sound output

As a total beginner, I have a project of creating an alarm device for a sailing boat. The background is the following: a Mac-mini collects, by means of different computer programs, alarms from ...
4
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5answers
41k views

Sine wave to square wave - Schmitt trigger

I need to transform a bipolar sine wave (varies from -5 V to 5 V, 1 kHz) to a square wave for further digital processing (0 to 3.3 V), as in this image: The important thing is ...
4
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4answers
257 views

Breakaway Glass Triggering

I need to electrically "sense" when a brick is thrown through a vertically-oriented pane of breakaway glass, breaking it. My first thought was to paint a thin strip of clear conductive ink/paint/gel ...
4
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2answers
803 views

Driving 74HC logic with sub-nano second clock reference

My goal: I am trying to phase lock a 74HC-based digital circuit from a clock reference at 10~15MHz pulse repetition rate. The pulse width is around 400 picosecond. The peak voltage is sometimes below ...
3
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2answers
531 views

How to measure switch bounce on a CRO?

I want to measure switch bounce, but all I have is access to an old CRO. Based on inputs from this forum post, I tried the HOLDOFF knobs and other buttons too. Nothing worked. In the case of modern ...
3
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4answers
9k views

Turn TTL output of logic IC into output capable of driving 50 ohm devices

I want to provide front-panel trigger signals with the microcontroller inside my device. The trigger signal will be fed via a 50 ohm coax cable to another device with a 50 ohm input. A direct ...
3
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2answers
383 views

Analog oscilloscope triggers

I have recently received an old 70's era Tektronix 465b dual trace oscilloscope. Unfortunately I have close to no clue how to use it. I understand the concept of triggering but this scope has two ...
3
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1answer
665 views

Why modern oscilloscopes use hardware triggering?

I've been learning how DSOs work for the past few days. As far as I understand, digital storage oscilloscopes have trigger circuitry, which usually consists of an analog comparator and a DAC. A ...
3
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2answers
691 views

Turning on and off car ignition - created two pulses?

I'm building a car DVR using a GoPro. The GoPro can be turned on by shorting out two pins on the gopro bus and then turned off by shorting out the same two pins. So when the car's ignition is turned ...
3
votes
1answer
771 views

How to store more waveform after trigger and less before?

I have a Rigol DS1074Z and can't figure out how to lower the time the scope spends pre-sampling to open up more memory for the actual data I want to see. Here is a nice image that will hopefully ...
2
votes
1answer
943 views

Issue getting relay to trigger, coil voltage might be insufficient

I have a simplisafe home alarm system. All components of the alarm(keypad, base station, sensors, alarm) are wireless, so there are no wires running to any sensors. I wanted to add an additional siren ...
2
votes
5answers
142 views

device for outputting HIGH when input have been HIGH?

I am looking for a device or circuit that outputs HIGH when a pushbutton has been pressed (if the button is pressed again it is supposed to still output HIGH), also, if possible, another pushbutton ...
2
votes
3answers
260 views

Digital trigger from a weak signal

I have a coin cell battery operated device that I'd like to detect a weak pulse. The device will be able to operate down to approx. 2.5 volt, so my Vref will be in the range 2.5 to 3V. The pulse ...
2
votes
1answer
489 views

Trigger switch using basic components

I am doing a project at a local fair which is one of those 'steady hands' games. I am adding a twist that if you touch the wire with the loop you are dragging through it once, distractions will start. ...
2
votes
1answer
589 views

Arduino flash trigger using laser and photodiode [closed]

I am trying to create a trigger for a high speed flash using an Arduino, a Sharp BS120 photodiode, and a laser pointer. The results i've obtained so far are inconsistent, the system seems to miss ...
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2answers
15k views

How does external trigger work in an oscilloscope?

I'm having hard time to find any easy explanation to understand how triggering and especially external triggering works. And it is even more confusing when a function generator's SYNC/TTL output is ...
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3answers
123 views

Can I use the external trigger to simultaneous capture waveforms on two oscilloscopes?

I want to look at synchronization in a 6 oscillator network (oscillators are about 100 kHz, 1.5 V_pp, if this matters). I have a 4 channel oscilloscope (Tektronix TDS 2024B) and a 2 channel ...
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2answers
198 views

Does CMOS J/K trigger need pull-up resistor

I want to use J/K trigger and I was told that usually IC outputs need pull-up resistor, but if I understand it correctly the following J/K trigger is based on CMOS: TI J/K trigger And it seems to me ...
1
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2answers
4k views

How to trigger triac using DC?

This video features a circuit that triggers a triac using a DC: https://www.youtube.com/watch?v=ZXXup79B6Gc I would like to make a little modification on it it. The video says that I have to connect ...
1
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1answer
71 views

Detecting “quick falls” in signal

I am conditioning the input of a slowly drifting analog input sensor. The sensor is a phototransistor that will sink a small amount of current when "dark" and 50x more current when "bright," but the ...
1
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2answers
308 views

What does “max” really mean in gate trigger threshold of a triac?

I am trying to understand the parameter Vgt (max) for a triac (or any semiconductor with a gate threshold parameter), mainly the max. part of it. For example, on page 2 of the following datasheet: ...
1
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1answer
326 views

How can I cause my oscilloscope to trig on interruption of AC voltage?

I'm probing a point with 230V RMS voltage inside a machine (don't worry, I'm using a 100:1 CAT 3 probe rated at 600V), and would like to trigger my oscilloscope at the point when this signal is ...
1
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1answer
136 views

Disconnect circuit after primary circuit detects high volume

I would like to build a circuit that detects high volume (through a microphone or something) and when it does, it would disconnect another circuit from its power source. I don't know exactly how high ...
1
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1answer
1k views

555 positive and negative edge detector?

Is there a circuit using the 555 (without additional logic gates) that creates a positive pulse when it detects a rising or falling edge? The goal is to have a circuit that detects when a signal goes ...
1
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1answer
488 views

Triggering a relay for a set period of time when voltage drops below a certain voltage

So I need a circuit, that will trigger a relay for approx. 10 seconds when the supply voltage of the device drops below 12.5 volts. Can anyone help me out? And also what might I need to change int ...
1
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1answer
65 views

Trigger Edge Detection Voltage issues

I'm trying to get an ESP8266 to wake up via external trigger. The trigger in this case is a PIR, which sends a 2+ second high signal when motion is detected. I'm using an edge detector to turn that ...
1
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2answers
68 views

Hardware triggering multiple devices from a single source for long distances

I need to trigger remote devices through their hardware trigger inputs simultaneously (within 1 ms) from a single trigger source which has a timer output. So basically the 0/5V pulse-train at around ...
1
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1answer
1k views

Why does this Edge Trigger Work on input of 555 monostable config?

I recently wired up a 555 timer in a mono stable configuration and found that when the trigger was held low for longer than the configured output pulse width, the output would stay high. After ...
1
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1answer
376 views

How does this temperature alarm circuit work

Casn you please help me understand how this temperature alarm circuit works? I am a bit over my head here, but I would very much like to understand this. If you would like to look at the multisim ...
1
vote
1answer
293 views

Simultaneous electronic shutter release for multiple Lumix G7 cameras

I'm trying to trigger six Panasonic Lumix G7 cameras at once. The trigger mechanism uses a four pole 2.5 mm plug, some resistors and two switches. With no switch closed there is 41 kilohms of ...
1
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1answer
306 views

Thyristor not switching on when 'cold'

I have breadboarded a simple circuit using a 2N6395 thyristor to drive a resistive load. In simulation all works well, and even the physical implementation works sometimes. simulate this circuit &...
1
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3answers
426 views

Trigger Signal Lockout Circuit

I have been trying to design a trigger lockout circuit and I have been having some difficulties. The circuit is taking as an input a 3.3v pulse. These inputs can happen randomly and what I would ...
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3answers
1k views

Control a switch with headphone output jack

So I recently finished my boombox project, but ran into a minor problem. The boombox is powered by a blue wrapped lithium ion battery and using a ta 2021 chip amp from parts express. If I plug the aux ...
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3answers
394 views

555 Timer Triggering Too Easily

I've got a 555 timer being powered by a 5v rail that is isolated from the 3v rail running a motor driver, which runs a motor. The 555 is only supposed to fire when it gets the signal from a 38khz ...
1
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1answer
46 views

Sine to sqare waveform but with variable peak-to-peak input

I need to calculate the speed of a little generator that produces a bipolar sinusoidal waveform with a peak to peak voltage value variable with the velocity. The produced signal also has a frequency ...
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0answers
64 views

1.8 V to 5.0 V level shifter with low delay and low rise time

i have a problem with finding the right components and circuit for the following problem. I have a device that is producing trigger signals with a length of 100 ns at a amplitude of 1.8 V (left part ...
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0answers
207 views

What is the correct method for Triac supply?

I need to know what is the correct power supply for fallowing light dimmer circuit that operate by 230V/50Hz AC supply. It should be neutral(N) to MT1 or live(L) to MT1? If can use both, what is the ...
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0answers
53 views

protect a driver for steep edges into capacitive load from external voltage

I want to have a 5V trigger output signal that has rising and falling edges of up to 200ns max. into a load of 1-5 nF. I thought about using MOSFET driver circuits (e.g. MC33152, many suppliers have ...
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0answers
866 views

How to make pulse wave from sine wave - audio frequency

I'm looking for a quick-and-dirty way of converting something close to a sine wave to a narrow pulse wave. Please see the image: a low bass note played through a broken transformer. I'm trying to re-...
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2answers
259 views

Altera III Cyclone FPGA input synchronization problem

I have a problem with the asynchronous input signal synchronization. I am trying to make the IIC_Slave based on Cyclone III FPGA Starter Kit. I saw 3 cases: If I do not use synchronization ...
0
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2answers
1k views

How to generate a single pulse using RC circuit from a fixed DC supply without any controller, timer or delay IC?

I have a DC supply (5 V) to turn some circuit on and in that circuit there is a module which uses a specific mechanism (i.e. a 2 seconds width high pulse) to turn on (even if a supply is connected, ...
0
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1answer
521 views

How to make a circuit to trigger a relay once the cell voltage reaches 83.5V DC

I need to make a circuit that will trigger a normally closed relay to cut a signal. I have a 12V power supply DC I need it to trigger once the main system reaches 83.5V DC Needs to be powered by the ...
0
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1answer
96 views

Step up voltage Transformer for more watt?

Using generator in mountain or underground tunnel location, construction workers from portable generator gets maximum: AC Output: 220volt as 200 to 250watt Now, they need to use a machine for ...