Homebrew PCBs

On 19/09/13 17:06, Robin Whittle wrote:
> With the 10W UV LED I described in recent messages, I measured the
> amount of light falling on a flat surface, like the PCB, according to
> how far from the direct perpendicular point of illumination this is.
...

Using this UV light meter, i found my pcb exposure box (75W mercury UV globe) 
gave 0.13mW/cm^2 at 60cm distance from the globe (it has a large parabolic 
reflector behind it).

Direct sunlight gave 6mw/cm^2.

If you could make an exposure box with UV sensor and automatic shutter, you 
could expose to sunlight in a matter of seconds. Even a cloudy overcast day gave 
more UV than my light box.

<http://www.ebay.com.au/itm/Brand-New-UV340B-Digital-Pocket-UV-Light-Meter-UVA-UVB-Measure-Tester-Gauge-/271133949389?pt=AU_B_I_Electrical_Test_Equipment&hash=item3f20d7bdcd>

Another meter:

<http://www.ebay.com.au/itm/UV-340A-Pocket-UV-Light-Meter-LUTRON-UV-340A-UVA-UVB-Measure-/271276514110?pt=AU_B_I_Electrical_Test_Equipment&hash=item3f29571b3e>