Uploaded July 2021 | Updated September 2026, 3 weeks ago
► $2 for 1-4 Layer PCBs, Get SMT Coupons: jlcpcb.com/DYE
This circuit is a Voltage/Phase Detector and works thanks to three BC547 transistors. The operation of the circuit is very simple, the small antenna is able to pick up the electromagnetic wave (EMF) emitted by the electric voltage.. this signal is amplified by the transistors, the third transistor acts as a switch and when signal reach its base it becomes closed switch and turn on the LED. This detector can be powered from 3 volts to 9 volts DC, I have prepared the PCB to house a 3 volt battery (CR2032). Read the list of components carefully if you want to power my project differently. It is designed to be used as a phase detector on medium voltage electrical systems (at 230v AC). Be very careful when using these tools, 230 Volt is very dangerous and can kill!
What is a phase detector?
A phase detector is a simple and inexpensive instrument used to detect the presence of electrical voltage on any circuit and in particular to identify the presence of a phase on a conductor. There are different types of phase detector, usually they have the shape and functionality of a screwdriver, but in the transparent and insulating handle there is a small neon lamp with an electrical resistance connected in series... one end of the circuit is connected to the tip of the screwdriver, the other to a plate on the handle. But this is my electronic version!
Components (if powered with 3 volt battery):
- 3x BC547 NPN Transistor
- 1x 5 mm LED (Red, Yellow or Green)
- 1x CR2032 Battery (3 volt)
- 1x CR2032 Battery Case
- 1x 100Ω Resistor (220Ω if powered with more than 5v)
- 1x 100KΩ Resistor
- 1x 560KΩ Resistor
- 1x 10uF (25/100v) Electrolytic Capacitor
- 1x On/Off Button with 4 Pin
- 1x Metal Wire 7cm (1 mm thickness)
If you add PWR Led:
- 1x 3/5 mm LED (Any color)
- 1x 1KΩ Resistor (if powered with more than 5v)
- 1x 330Ω Resisrtor (if powered with less than 5v)
- PCB: drive.google.com/file/d/1LrOHcSialcOd3WU_49JcsHKk1Rdqzk22/view?usp=sharing
*Don't use my PCB for profit or sponsored videos.
Features of this PCB project:
- Layers: 2 (with Through PAD)
- For 230 Volt AC Systems
- No contact needed with AC Voltage
- Working voltage: 3v with CR2032 Battery
- PCB Size: 23 mm* 94 mm
- PCB Thickness: 1.6mm
- PCB Color: Red
- Silkscreen: White
- Surface Finish:HASL (with lead)
- Material Type: FR4-Standard Tg 130-140C
WARNING ⚠ - 230 Volt is very dangerous and can kill
► PROS and CONS of this circuit:
🟢 PROS: Simple, Functional, Economical, Portable and Contactless
🔴 CONS: Subject to external EMF, Not for professional use
For any other questions you can ask me for explanations in the video comments:)
✅ Subscribe to my YouTube channel It's FREE!
Chapters:
0:00 - Intro
0:50 - Circuit Diagram
0:56 - Circuit Explanation
2:05 - Unboxing
2:40 - Start Assembly
5:18 - Test
6:10 - END
■▬▬▬▬▬ LINK & Support ▬▬▬▬▬■
✅ YouTube: youtube.com/c/Stefano91ste
✅ Instagram: instagram.com/Stefano91ste
✅ Pinterest: https://www.pinterest.it/Stefano91ste
✅ My STORE: youtube.com/c/Stefano91ste/store
Watch another video =)
● Music Keyboard: youtu.be/ajtR6eDOaQI
● LED Water Level: youtu.be/n9GB0nfwG8s
● Police Light: youtu.be/PtmEqcRbu4w
● Vu-Meter Stereo: youtu.be/l8oUQpGAOCw
● Traffic Light: youtu.be/6iRjZMHVvhs
● Vu-Meter 40 LED: youtu.be/oWB2faToGAA
WARNING: This video is only for demonstration. I don't take any responsibility.
#VOLTAGE #DETECTOR #diyprojects
► $2 for 1-4 Layer PCBs, Get SMT Coupons: jlcpcb.com/DYE
This circuit is a Voltage/Phase Detector and works thanks to three BC547 transistors. The operation of the circuit is very simple, the small antenna is able to pick up the electromagnetic wave (EMF) emitted by the electric voltage.. this signal is amplified by the transistors, the third transistor acts as a switch and when signal reach its base it becomes closed switch and turn on the LED. This detector can be powered from 3 volts to 9 volts DC, I have prepared the PCB to house a 3 volt battery (CR2032). Read the list of components carefully if you want to power my project differently. It is designed to be used as a phase detector on medium voltage electrical systems (at 230v AC). Be very careful when using these tools, 230 Volt is very dangerous and can kill!
What is a phase detector?
A phase detector is a simple and inexpensive instrument used to detect the presence of electrical voltage on any circuit and in particular to identify the presence of a phase on a conductor. There are different types of phase detector, usually they have the shape and functionality of a screwdriver, but in the transparent and insulating handle there is a small neon lamp with an electrical resistance connected in series... one end of the circuit is connected to the tip of the screwdriver, the other to a plate on the handle. But this is my electronic version!
Components (if powered with 3 volt battery):
- 3x BC547 NPN Transistor
- 1x 5 mm LED (Red, Yellow or Green)
- 1x CR2032 Battery (3 volt)
- 1x CR2032 Battery Case
- 1x 100Ω Resistor (220Ω if powered with more than 5v)
- 1x 100KΩ Resistor
- 1x 560KΩ Resistor
- 1x 10uF (25/100v) Electrolytic Capacitor
- 1x On/Off Button with 4 Pin
- 1x Metal Wire 7cm (1 mm thickness)
If you add PWR Led:
- 1x 3/5 mm LED (Any color)
- 1x 1KΩ Resistor (if powered with more than 5v)
- 1x 330Ω Resisrtor (if powered with less than 5v)
- PCB: drive.google.com/file/d/1LrOHcSialcOd3WU_49JcsHKk1Rdqzk22/view?usp=sharing
*Don't use my PCB for profit or sponsored videos.
Features of this PCB project:
- Layers: 2 (with Through PAD)
- For 230 Volt AC Systems
- No contact needed with AC Voltage
- Working voltage: 3v with CR2032 Battery
- PCB Size: 23 mm* 94 mm
- PCB Thickness: 1.6mm
- PCB Color: Red
- Silkscreen: White
- Surface Finish:HASL (with lead)
- Material Type: FR4-Standard Tg 130-140C
WARNING ⚠ - 230 Volt is very dangerous and can kill
► PROS and CONS of this circuit:
🟢 PROS: Simple, Functional, Economical, Portable and Contactless
🔴 CONS: Subject to external EMF, Not for professional use
For any other questions you can ask me for explanations in the video comments:)
✅ Subscribe to my YouTube channel It's FREE!
Chapters:
0:00 - Intro
0:50 - Circuit Diagram
0:56 - Circuit Explanation
2:05 - Unboxing
2:40 - Start Assembly
5:18 - Test
6:10 - END
■▬▬▬▬▬ LINK & Support ▬▬▬▬▬■
✅ YouTube: youtube.com/c/Stefano91ste
✅ Instagram: instagram.com/Stefano91ste
✅ Pinterest: https://www.pinterest.it/Stefano91ste
✅ My STORE: youtube.com/c/Stefano91ste/store
Watch another video =)
● Music Keyboard: youtu.be/ajtR6eDOaQI
● LED Water Level: youtu.be/n9GB0nfwG8s
● Police Light: youtu.be/PtmEqcRbu4w
● Vu-Meter Stereo: youtu.be/l8oUQpGAOCw
● Traffic Light: youtu.be/6iRjZMHVvhs
● Vu-Meter 40 LED: youtu.be/oWB2faToGAA
WARNING: This video is only for demonstration. I don't take any responsibility.
#VOLTAGE #DETECTOR #diyprojects
