05-02-2013, 10:38 PM
Well, all depends on whether the heat has a way of escaping. You do realize that even a low temp heater if well insulated can deliver enough heat to ignite just about anything.
A good example is when old lampshades were covered with newspapers and would catch fire.
However 7W (and a 7W resistor will not be made to dissipate 7W; it is probably 3-4W) is not 40-70W of an incandescent lightbulb, and thisck wood is not thin paper, and the heat has some way of escaping as the radios were designed with this in mind (well, most of them, I guess).
A good example is when old lampshades were covered with newspapers and would catch fire.
However 7W (and a 7W resistor will not be made to dissipate 7W; it is probably 3-4W) is not 40-70W of an incandescent lightbulb, and thisck wood is not thin paper, and the heat has some way of escaping as the radios were designed with this in mind (well, most of them, I guess).
