Here is a simple tool to check the degree of radiation from an electric or electronic instrument. The LEDs in the circuit will give a running light pattern at the moment the circuit senses electromagnetic radiation from the device. It can detect radiation from the Computer or TV from a distance of 2 feet or more.
The speed of running light depends on the intensity of radiation. Fast running light indicates high amount of radiation and vice versa.
IC CD4033 is the decade counter with7 segment display driver. It has seven outputs to drive LEDs or Seven segment display. The clock input (pin1) of IC is very sensitive and readily accepts energy from the electromagnetic radiation even from a long distance. This property of the IC CD4033 is exploited here to measure the intensity of radiation. The reset pin 15 of IC is connected to C1 and R1 to reset the IC after completing a cycle. So that the functioning of IC continues till the input pulses cease.
A small length plastic wire can be used as areal. A telescopic areal used in pocket radio will give an elegant look to the gadget
Bring the areal close to the TV or CRT monitor of computer. All the LEDs light up one by one giving a running pattern. The speed of running light depends on the strength of radiation. Move away the unit from the monitor. As the diastance increases, speed of running light decreases. Finally all the LEDs stop glowing. This is the point without the radiation. Check all the electric instruments and mains wiring using the device and find out how much radiation is emitting.