Contactless Voltage Detector 

hope this helps for those whose circuit LED is stuck in the ON state: for future reference for some weird reason, it only work for me when i have the led to Vcc and the negative of the led on the output of the ne555 pulling it up rather than down..... i checked it on a scope and when the circuit triggered, the output pin connected to ground so when voltage was present it started to flicker as the NE555 tried connecting it to ground, both pins are ground so it turned off. The off time was very short compared to the on time so it seemed like it was flickery but on In the other case where + of led is at Vcc and - of led is at pin 3 of the IC, in no trigger state, the LED is off, when a trigger is there it was connected to ground and the LED was on and flickering. I also saw the intensity was in two states, low and high, in low it was very flickery and dim and when it is very close it becomes very bright and flicker is less also i had the reset pin connected to Vcc as its active low, to ensure the IC is held in ON state rather than reset state, it didnt check it without the reset being connected but it will also help if you face issues

Nicely done. Feel the urge to make one myself!

Excellent descriptions, graphics, and overall tutorial of the design process in general. With about a half-century of experience, I would like to add a safety suggestion. These types of non-contact devices are great for checking presence or absence of voltage, such as for checking a switch or tripped breaker. However, if you plan to touch conductors, use a proper multimeter or tester designed to actually touch the wires, and test it on a known live circuit beforehand to ensure it works properly. There are some cases where these non-contact devices can read a false negative, where power is really there, but not read by the tester due to other unforeseen electromagnetic influences. This applies to the commercial units as well.

That's impressive, but you can buy one for under $20, sometimes even under $10. However, "Because you can" is often something I admire!

never stop please its a request keep making video

Can this be adjusted so that only detects when current is flowing? Not just voltage present

Genuine, amazing and Intelligent

Very well presented, Sir you are great

First... thank you very much for this excellent video, is crystal clear! ...second ... is possible to measure the voltage that you are detecting? I would like to use the first project due to is very sensible, I want to read, show an store the values read by the device, do you think is posible?

Hello. If I connect the output of the 555IC circuit to the input of a low wattage FM transmitter circuit, will the signal be broadcasted? How does one calculate the voltage drop of the 555 circuit? How would one change the 555 circuit output frequency and duration? Thanks for your very well-presented demonstration and your advice.

Had some components and thought why not, I didnt have a 4.7uf cap, used a 10uf electrlytic cap, was missing 220ohm resistor so used 1k 😅. But it works like a charm (kinda). Very cool concept. Thanks for teaching. P.S. Please post more videos. Really helps A LOT. I am doing my first year of electronics and comms engineering, really frustrating as I have inadequate lecturers. For example your transistor explanation video, never understood the concept of "flow of holes" until I saw your video. The visualisation helps A LOT. That been said. Thank you A LOT.

Good work brother

Amazing...... the circuit using IC 555 is more reliable out of the three Circuits as explained by the "Crazy Couple DIY" very professionally.

Wowwww great info 👍🏼

very good video and easy to follow

how you can you change the sensibility in the 555 configuration?

How thick is the antena wire in the 555 circuit. Thanks

Thanks a lot for the comparative study, helped me choose the 555.

Thanks for sharing this video keep it up and stay connected your friend love till the end

Does your 555 circuit detect incorect switching power supply connection when there is AC present on the device cover like PC PSU.

And bro I like that how till now after 2 years you are seeing comments.big fan

I made this 3 times but buzzer and light continuously ringing also light flashes no any thing detecting

Awesome video

The last one is is based on capacitive coupling not inductive coupling, larger surface area for the antenna will hugely improve it.

Continue doing these and Arduino type of videos. They are really helpfull.

Awesome man

I built the 555 circuit and followed the schematic/instructions precisely but the LED stays on constantly. The buzzer works fine however. I've tested it with both 9v battery and 5v (arduino). This is for a school project so it has to work exactly right. Any suggestions?

The 555 circuit looks like it could be used to check for cables behind plasterboard walls. Will give this circuit a go for sure!

Awesome perfect genius video 👍👍👍👍👌❤️

I want a temporary indication of the presence of voltage. Buzzer for ten seconds?

Is the ic555 single timer?

رائع جدا كالعادة شكرا على هذا العمل المتقن.

perfect, thank you

Well explained...good.dupet

Please answer one question...if i want to detect 11 kv while standing on ground,will these ckt help,,,the 11 kv wires are approx at 8 -9 meters from the ground level...if no then how to increase the senstivity of this ckt so that I could detect 11 kv voltage while standing at ground level just by raising ckt in my hand safely,,, as it's risky to go near 11 kv

Super video. Clear explanation. Please upload gold metal detector circuit. Thanks.❤

Ok... But what is ac voltage in your location? 127v phase-neutral or 220 volts phase-neutral? Thanks!

In first project using IC 4017 what is the use of placing 2n2222 transistor

Once I used the IC 555 in an oscillating circuit, when I applied a voltage difference of 9 V, it burned and stopped working. Is a 9 V battery burnt the integrated 555

Thanks, I'd been wondering why so many people use IC sockets; cheap soldering irons :)

What is the voltage value of capacitor

whats minimal voltage?

thanks very much for sharing

Can any of these circuits tell the difference between: 1. A power cord that's plugged into the mains. 2. A power cord that's plugged into the mains and connected to a load?

A lot of thing to learn

please in which mode this ic 555 timer is working in this circuit and thank you

useful 👍

Hi i just want to ask if this DIY can detect a voltage on motorcycle with a 12v supply voltage? Thanks

I tried ic555 and it burned I followed everything to the letter I do not understand what I wrong

Can wa use 3volt battery instead of 9 v battery in 555 circuit pls replay

Para funcionar o 555 não ligue em fonte. Precisa ser na bateria caso contrário ele fica disparado

Very nice and informative..🙂 My question is about the ne555 ic ..can I use pot instead of 1k resistor to adjust the sensitivity of the tester?..

nice trick with the 555.

hi, great project! tell me, can this detect live wire inside walls? tnx.

Muito bom 👏👏👏

very interesting & wonderful circuit. 🥳 Do you have a non-contact circuit to indicate 3 phase [A-B-C] 2,300 volts AC motor rotation sequence? 😎 Thank you. Most 3 phase motor rotation direction "CW or CCW" testers only go to 700vac.

in the last test you are using battery of 9v, but in the draw 5 volts?

Can I use LM386 instead of 555 with same circuit ?

From which distance can this circuit detect three wired cable with good ground line?

What pins and what board (the orange thing with sockets) are you using to put in all the wires and hardware in the 555 IC? Can you detail what brand you are using as well because that would help a lot.

Tq sir Usefull your vidio

this is nice. Ist here a commercially available module or gizmo that does this?

Its good...tnx...boss.

Can I check the 11 KV line with this. ?

Could you please share the 555pin numbers along?

can i use any else capacitor?i don't have 4.7uf

You didn't specify how many voltage for the 4.7uF capacitor?

How many volts should the capacitor ?

Perfect

can i check 12v dc voltage's wire?

Can we use a BC547 for this?

I made using transistors. It really works!!

What features does the buzzer have? how many volts does it work?

I created this project, it is working fine. But sometimes it continues give alarm even if it is removed from the cable. What can I do?

can i use one of this? NE555PWR, NE555P, NE555D? i can't find NE555N.

Can it detector a voltage inside the wall ?

Nice

Sir can you tell me Why does it happen when i touch my fingers to the antenna , led glows and buzzer beep? (In case of when we use transistors) Plzz tell me sir

Will it work for Dc current also?

Hello, thank you very much. Please explain how to make a good metal detector so that I can make one. I always thank you, engineer.

Can using different transistor make it detect lower voltages?

I like the 555 ic as you like but after some time it is automatically blinking and buger is also working automatically. With out bring a live wire next to it please tell me a solution .

witch voltege for capasitor 4.7uf

is it gonna work if i wire the speaker and the led 25 meter away from the amp?

I am still getting false reading in. 555 ic .what to do?

it will work at which voltage.

Great informative

Sir i m using 4.7 uf 50v capacitor and 10k resistor but it beeps continuously

hi can we use this circuit in an 8kV AC supply?

You are really master sent me other videos

can this voltage detecter high voltage detect?

This can only detect AC voltage , can it detect DC volatge?

4.7 uf capacitor volt's?

Capacitor 100UF but what volt? 4017

Good work

Can we use this in water to detect electricity leakage

Funciona com pilha de 3v?

I just tried your second project but it was not working totally failure

Good

What is the voltage of the capacitor?