Test Lamp as a fuse info???

[Zero Cool]

I have seen many repair shops use a standard household light bulb in place of a fuse for testing unknown devices that might have an internal short. This seems to be a pretty common thing.

AND, some speaker companies use fuses in the crossover circuits as current limiting devices.

Where can i find info on what wattage rating bulbs to use for functions as such??

For example. if i am testing a power amp. is a standard 60 watt bulb sufficient? or is there some rule of thimb to size the bulb by????

If i want to limit current to a speaker driver, how do i calculate the bulb???

Is it a 1:1 ratio??? 60 watt bulb limits current draw to 60 watts or????

[djk]

For the majority of class AB amplifiers 100W or less, I recommend a 75W 120V bulb. A high bias, high power amp like a Hafler DH500 will need a 150W 120V bulb.

As regards speaker protection, it is best used on tweeters only. For 1" voice coils the 211-2 automotive dome lamp works best. For compression drivers with nominal 1.75" coils the 1156 automotive back-up lamp works best.

[Zero Cool]

Originally posted by djk
For the majority of class AB amplifiers 100W or less, I recommend a 75W 120V bulb. A high bias, high power amp like a Hafler DH500 will need a 150W 120V bulb.

As regards speaker protection, it is best used on tweeters only. For 1" voice coils the 211-2 automotive dome lamp works best. For compression drivers with nominal 1.75" coils the 1156 automotive back-up lamp works best.

Perfect, i will give those a try. just out of curiousity? is there any rhyme or reason to these???

[Zero Cool]

Bump....Anyone???