# PocketMagic

Where Technology meets magic

Android
50 Posts
BlackBerry
6 Posts
Electronics
79 Posts
Hardware
136 Posts
High Voltage
53 Posts
Image processing
5 Posts
iPhone
4 Posts
Linux
2 Posts
Nuclear
26 Posts
Optics
11 Posts
Photography
7 Posts
Photoshop
3 Posts
Research
20 Posts
Reviews
18 Posts
Robotics
8 Posts
Security
8 Posts
Software
86 Posts
Symbian
2 Posts
Tubes
23 Posts
Windows Mobile
11 Posts

### Top Articles!

 Bluetooth and iOS - Use Bluetooth in your iPhone apps Simple Switched power Supplies uRADMonitor - Online Radiation monitoring station Building a robot – Part 2

2013-12-01, DIY/Homemade Geiger Muller Digital Counter V3

2013-11-25, Complex Android GridView with Drag and Drop functionality

2013-11-24, Simple Gridview Control for Android

2013-11-22, Tube: SI-29BG (CИ-29БГ) Sensitive Small Geiger Muller

#### By Radu Motisan Posted on November 29th, 2010 , 4053 Views (Rate 3.68)

For my High voltage experiments, knowing the exact potential difference of a given supply value would be extremely useful. So I decided to build a high voltage probe, using a resistive divider. After doing some calculations, I decided to go for a 1:1000 divider ratio, for the many advantages including ease of reading the measured values (10kV -> 10V).

The High voltage goes as Vin, and the measurement is done at Vout.
I needed a 1GOhm resistor, so I purchased 5x 200MO Vishay Dale High voltage resistors from Ebay. Connecting them in series I get the desired value:

To insulate this resistor, I put it in a PVC pipe under oil:

If R1 is 1GOhm, and R2 is 1MOhm, the voltage drop across R2 , Vout will be aprox. 1/1000 * Vin . Instead of R2 I use a multimeter with 1MOhm impedance (However, to protect the multimeter, additional components are required). The results:

The left picture shows a good result: for 30.3V in, the multimeter measures 32mV, very close to the 1/1000 ratio (actually the ratio is 1/1001).

However, trying to use this probe with my 50KV supply, gives very poor results. The multimeter jumps between values, the biggest shown is 12 (12KV). Probably because of the high frequency currents.

### More on PocketMagic:

 A 3D Carousel View for Android NMEA GPS Library for AVR Microcontrollers Variable 0..30V Regulated Power supply for 20A max Global radiation monitoring network Complex Android GridView with Drag and Drop functionality Coil Winding machine counter with Atmega8 and Reed relay

### 3 Responses to “Homemade/DIY High voltage probe”

1. 1
Miguel Angel Santos:

lo voy aprobar despues cuento

2. 2
Mihai:

I am interested to make some HV and HF probes and I found this material ; maybe will be helpfull for you to design your own probes: