Questions tagged [detector]

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9
votes
6answers
742 views

A few questions on PIRs and other motion detectors

I grew up incorrectly believing that motion detectors (as part of burglar alarm systems) were designed to detect movement, when in actual fact it is the movement of a heated (like body heat) object ...
0
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1answer
53 views

Circuit to detect only one zero crossing when a sine wave changes from negative to positive half cycle

In a Grid Tie Inverter design, I need a circuit which can detect only one zero crossing of the Grid signal, (when the signal will change from negative to positive half cycle). I have made a circuit, ...
1
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1answer
80 views

Detecting a location of the needle inside a cavity having multiple IR emitters , using IR Detector at the tip of the needle

I am working on a project where I need to find the location of a needle that has the IR detector at the tip of the needle. These needles are medical suturing needles that would help us to detect the ...
0
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1answer
54 views

Microwave detection circuit verification

I want to develop a circuit which can detect electromagnetic waves (radio wave, microwaves.) This circuit will just act as a tamper detect and not physically measure/compute the radiation. I have ...
0
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1answer
96 views

Metal detector circuit description

I found a circuit for this metal detector and would like to make PCB. I can not find anything about this circuit. Maybe someone would know what this circuit is. What are the best component housings to ...
0
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1answer
149 views

Why are alkalines “required” for metal detectors?

A handheld metal detector specifies only "Alkaline" batteries and not "heavy duty" or "rechargeable". Since there are li-ion 9v batteries available not at low cost I was ...
0
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1answer
50 views

Designing a Light/Dark Sensor with LDR 555 alternator LED and Motor

I am working on a project which I need to turn on LED alternately as well as motor turned on while it is dark. I managed to create an Electric circuit which can turn on the LEDs together. However ...
0
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0answers
22 views

Feed-through termination to vary bandwidth and signal power

I'm currently facing an interesting problem regarding RC low-pass filters. In my experimental setup, I have a reverse-biased photodetector (DET01CFC from Thorlabs). To amplify this signal, I make use ...
0
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1answer
83 views

Is this a demodulated signal?

1st attempt I have a problem. I built the FM demodulator circuit, but i am not sure if this signal is demodulated. This was my first attempt which following an answer, resulted in a 2nd attempt ...
1
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1answer
63 views

How to balance antiphase Rx coil in metal detector?

In this question How can I drive an LC tank circuit to get a nice and clean sine wave? I learned to get clean oscillation waves of a tank circuit (Tx) and consequently its reception through antiphase ...
2
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3answers
182 views

How can I drive an LC tank circuit to get a nice and clean sine wave?

As advised by Andy in this post, I constructed single loop transmit and receive coils: I use this circuit to transmit a powerful field: The Tx signal has a large spike that is reflected in the Rx ...
0
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1answer
88 views

Linear regulator power consumption

I have this circuit linear regulator with UVLO so I would like to calculate the power consumption of this block any person can help me, please Vout = 1.5 V (Iss = 15.2 μA, Vout = 1.5 V, switching = 32....
1
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1answer
218 views

Envelope detector RC values [closed]

I have understood how the envelope detector works, but I am unable to find the formula for R and C appropriate values. The closest I have found is this link: Explain The Square Law Demodulation and ...
0
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0answers
28 views

Maximizing signal to noise ratio for very small radiation detector

I have a very small radiation detector that outputs signal of small amplitude. Requires preamplification before going to an actual amplifier. When constructing the system prior to the preamp, would I ...
0
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1answer
56 views

How do I calculate the power consumption of the polarity detector circuit?

What method can I use to calculate the power consumption of this block? In the paper it's equal to 3 μW at 1.5 V. The datasheet of the piezo sensor. The datasheet of the MAX9119 comparator. Circuit:
0
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1answer
113 views

How does this under voltage lockout (UVLO) work?

In my project, I need an under voltage lockout (UVLO) to connect the load electronics to the energy-storage element via a power-gating transistor when the voltage across the supercapacitor exceeds ...
1
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1answer
234 views

Help choosing modern replacement for Hitachi 1SS86 Schottky diode

I’m trying to find a modern Schottky diode to use instead of the 1SS86 Schottky diode (Hitachi version, specifically). I want to use it along with a low current LED to build a lectenna that works for ...
0
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0answers
45 views

Fisher Scientific T-30 Metal Detector - Circuit schematic

Looking for service manual for this old thing or a very similar detector it is from 1965 with germanium transistors .. I didn't think there was any real use for it until someone asked .. some photos ...
1
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2answers
128 views

Infant cry detector

I want to use an electret microphone to detect infant cry. I came up with this design: According to those papers: Pitch Analysis of Infant Crying Frequential Characterization of Healthy and ...
1
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1answer
67 views

Amplitude detection

Why is second analog multiplier(marked with red color) used to detect the amplitude of the input signal in this circuit instead of diode? The point of this circuit is to maintain the output level of ...
1
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1answer
130 views

Simulation of voltage sensitivity of ideal detector diode circuit

Application note 969 derives the voltage sensitivity at zero bias of a detector diode: \$ \gamma = \frac{V_o}{P_{\rm in}} = \frac{0.52}{I_s(1+\omega^2 C_{j0}^2 R_S R_V)} \cdot \frac{R_L}{R_V+R_L}, \$ ...
1
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2answers
88 views

Switch off power when 0v is sensed / Short to ground

I have already posted this question but I made a mess of the diagram so deleted it and am posting again, apologies to anyone to answered the original question. I'm fairly new to electronics and am ...
0
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2answers
148 views

How would i go about detecting if a rs-485 cable is plugged in?

The basic problem were trying to solve is certain secondary device's cables gets left unplugged and we need a way to detect a cable that is plugged into my device,and check if that cable is actually ...
0
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0answers
48 views

Transformer-insulated flame ionization detector. How to improve response? Triode, messure current safety, ignition fires

I am trying to do a isolate flame ionization detector with a transformer ignition. But, when I put it on the frame, nothing change.. (0.2VAC) I put a amplifier (10 teraohms impedance) to read the ...
3
votes
2answers
92 views

Use of ceramic capacitors in HV system

When I opened the supply board to the detector (Geiger counter,) I got the above circuit. The detector uses a gas-filled tube with a central wire at high voltage to collect the ionization (charge) ...
0
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2answers
75 views

Sequence Detector forced to wait a specific number of bits

So I have this little problem, where I am supposed to build a sequence detector which is forced to wait a specific number of bits before going into the reset state. It's kind of like pin codes work. ...
1
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3answers
568 views

Most simple way to detect small voltage changes(~150mV)

I have one unit of museum cabinet detector that works on 18v. I want make simple security circuit with detector. I've figured out that two output ports on detector are normally contact(NC), but it'll ...
0
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1answer
251 views

Defect LED detection for car lights

The schematic beneath is a new project of me. The theory behind this is: My car has a very fool proof bulb failure detection and warning system. CANbus proof LED bulbs can't fool the car and just a ...
3
votes
1answer
67 views

Noise in crystal detectors (historical)

I'm reading over the history of British WWII radar systems, and one thing that really struck me was the improvement in crystal detectors. The were a vital component of microwave radars, and while the ...
0
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2answers
485 views

How inductance of a coil changes when there is a metal object nearby?

I am not sure if it is increasing or decreasing as some sources say it is increasing whereas some say it is not. What actually happens when a metallic object is put under a coil that is meant to be ...
0
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1answer
101 views

NC Opening Contact detector to drive a NO relay Contact circuit

I'm looking for a simple +5.5vdc powered circuit (perhaps a PNP transistor driving a NO Reed Relay coil?) - I need a circuit that can detect when a pair of Normally Closed contacts with no voltage ...
0
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1answer
31 views

Motion Detector Time Adjustment

What it means when adjustment area is: 10±5 s-10min? I cannot find a solution from Google.
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2answers
114 views

Automotive tachometer signal interpretation

I'm trying to build a custom dashboard for a car (Daewoo Lanos 1998 with Delco ECU). Tachometer signal, that comes to dashboard with a separate wire looks a bit strange to me. It seems that the signal ...
0
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0answers
88 views

Choosing a suitable PFD for PLL

I'm building a capacitive vibration sensor and it has to reject the stray capacitance by locking the LC oscillator at 64 MHz, where I can demodulate relatively small frequency changes. The best way to ...
0
votes
1answer
488 views

LTSpice - envelope detector LPF behaving like buffer

I have an issue with an LTSpice simulation and I'm not sure if the issue lies in the simulation setup or somewhere more basic. The simulation is as follows: The system is as follows: on the left, ...
-4
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1answer
76 views

do is anyway to detect Tablets Pills package is empty or not? [closed]

do infrared sensor can pass through transparent plastic and work?
0
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0answers
221 views

Understanding the basics of AC coupling

The real case I am working on: I need to connect a CZT (Cadmium-Zinc-Tellurium) detector to a custom ASIC input (a Charge Sensitive Amplifier of which I do not know the input impedance, if that ...
0
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1answer
131 views

Missing pulse detector for low input?

I'm looking to implement a watchdog circuit. Tried the standard "missing pulse detector" schematic such as one from http://www.falstad.com/circuit/e-555missing.html - and it works well when the input ...
0
votes
1answer
56 views

Can you convert a headphone into a metal detector coil?

I was wondering if it's possible to convert a stereo headphone into a coil to be used as a signal transmitter and receiver for metal detecting? The idea is to use a smartphone as a signal generator.
1
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2answers
458 views

Comparator as a current detector

I'm looking for a simple circuit that uses only a comparator (or an opamp) to detect the presence of a small current through a high-side current resistor. The idea is for a microcontroller input to go ...
4
votes
2answers
98 views

Reducing the range of a D flip-flop frequency detector

I'm designing a frequency tracking circuit and I came up with a circuit that tracks frequencies from Fclk to Fclk/2: However, it would be very nice if the bandwidth was a bit narrower, from Fclk to ...
2
votes
2answers
121 views

Is it possible to convert the audio signal from a smartphone's headphone jack into radiowaves? [closed]

I was watching a video of someone using his smartphone and a custom designed coil to make a metal detector. The smartphone was connected to the coil via headphone jack. I couldn't understand how he ...
2
votes
2answers
2k views

Bandpass Filter: Single supply op amp design

I have taken on a hobby project and I am trying to make a circuit which would be able to identify an acoustic signal with a frequency of 40kHz. Here is the circuit of a band pass filter for this: ...
-1
votes
1answer
152 views

My mobile detector circuit won't work

I'm trying to get C3 to detect RF signals from a mobile phone. Amplify this signal to detect it using an LED. My main issue is simulating the antenna on multisim since multisim doesnt have an antenna!
0
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1answer
98 views

Electronic detector to measure of distance? [closed]

I am not well known about electronic and it is my first question here, beforehand sorry for not qualified question. Let me try to explain what I am looking for: Is there chip or any another ...
2
votes
2answers
154 views

Is there a simple way to detect which connector is powered?

I have a circuit with two power connectors, J1 and J2. I would like to be able to detect which one the power is coming from. The trick is that the connectors need to provide power to each other. ...
1
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0answers
3k views

Metal Detector using IC 555 Timer project

I want to build some project about metal detector using integrated circuit 555 timer. I already made a schematic in proteus 8 application. I made some change with the original schematic i found on ...
1
vote
1answer
261 views

How to calculate noise power (dBm) of a photodiode?

I want to check the thermal noise spectrum of a photodiode (PD) at different frequency response but I do not know how to calculate it. Below graph is an example which shows noise power (dBm) as a ...
1
vote
2answers
711 views

Non contact (contactless) AC or DC detection?

I'd like to detect AC or DC current (not the current level just nothing or something => ON/OFF) in a wire with a (DIY) sensor just in contact (glued) with the wire plastic insulator. At the end the ...
-4
votes
3answers
340 views

How do I reverse-bias a resistor?

We all know that a photo diode can be used as a light detector and as a light emitter (although the way that it's built will usually make it specialized to prioritize one application over the other); ...