Non-contact voltage testers are probably the safest testers
around, and they're certainly the easiest to use. A non-contact tester allows you to check for voltage in
wires or devices without you having to touch any wires or parts.
Features
1. Auto power-off
function.
2. No On/OFF
switch required.
3. Non-contact
detection of AC voltage from 40 V to 600 V with LED light.
4. Battery life
on standby mode up to two years.
Parts
List
|
|
Resistor
|
|
R1
|
1M Ohms
|
R2
|
10K Ohms
|
R3
|
100 Ohms
|
Transistor
|
|
Q1
|
BC547
|
Q2
|
BC557
|
Additional parts
|
|
LED
|
Red
|
Battery
|
LR44 x 2 (3V DC)
|
Test probe
|
3cm to 5cm copper wire
3mm diameter
|
Touch probe
|
1cm diameter copper
clad board or aluminum foil
|
Common PCB
|
|
