Re: [APD] DIY jobs

[Nicolas Munro <nmunro at qld_yokogawa.com.au>]

Have you looked into this AC vs DC?   I would have thought/assumed (non 
researched) that the fish would be more affected by the AC signal as its 
always changing. EMF goes one way then back the other way, 50 or 60 
times a second??

Either way do the fish just get use to it and accept the EMF / magnetics 
after a while?



=Nick
PS: use a diode in reverse direction and a opamp to measure the temp of 
the resistor, you should (with a fancy circuit) make it stable and self 
regulating to reduce the amount of current required.



Stuart Halliday wrote:

>Mariano F. Bonfante wrote:
>  
>
>>Local outlets has 220V 50Hz, so I am using a 60Vca (typical en CATV 
>>industry), galvanic insulation transformer for feeding the resistors. There 
>>is also a dimmer circuit, to allow two phases: day and night. Daytime 
>>permits the substrate to be 1ºC above the water, nigh phase just a bias 
>>voltage.
>>    
>>
>
>  
>
>>I spent some time with these systems, but it is fun and I like it.
>>    
>>
>
>Cute.
>I'm a IT engineer, who was a electronic engineer, so I've often built my 
>own low powered heaters for small Aquariums.
>
>I put the resistors in a test tube and fed them 18V DC @ 1.1A from a 
>basic regulated off the shelf DC power supply.
>So no risk of electric shock or it failing like normal heaters.
>
>It has as a side effect, a low electromagnetic field due to its use of 
>DC as oppose to using AC. Some say fish are sensitive to these fields.
>
>  
>
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