Originally Posted by DMRider_10
So using a cap rated to a higher voltage is ok practice? I had to source one recently to replace a 0.1uf 50v cap and could only find a 0.1uf 100v cap, that will be ok then>?
Yes. The voltage rating on a capacitor tells you what the maximum
voltage you can apply to the capacitor is without causing it to fail. With ceramic caps in particular, it is almost always permissible to substitute a part with a higher voltage rating.
The same goes for diodes. Take the common 1N4001, for instance. It is rated to pass 1A continuous forward current, while causing a maximum of 1V forward drop. It is rated to withstand a maximum of 50V peak reverse voltage. There are six other common diodes in this family, the 1N4002, 1N4003, ..., 1N4007. The only difference between these is that the 4002 is rated for 100V peak reverse, the 4003 for 200V peak reverse, ..., and the 4007 for 1000V peak reverse. So it is always OK to substitute a 1N4002, for instance, in a place where a 1N4001 is called for.
Ditto resistor with their wattage ratings. The only difference between a 1kΩ 1/8 watt resistor and a 1kΩ 1/4 watt resistor (apart from physical size) is that the latter is capable of surviving twice as much power without bursting into flames. So you can always substitute a higher wattage resistor for a lower wattage one, assuming the resistance valve and tolerance are respected.
Similar substitutions apply to transistors, FETs, and even a lot of IC classes (such as op-amps) although the rules are more complicated.