Thursday, November 12, 2009

Light bulb current limiter

After a trip to Lowes and scrounging around in the garage the limiter is built. When first powering on a newly built amplifier, use a bulb limiter or Variac. It will keep you from destroying some very expensive parts if there is any problem with your amp. The picture shows a 75-100 watt lamp, but I typically use a 25-60 watt to start with. If there's something wrong with an amp, it will draw too much current and the light bulb will blow. But it's better to blow a light bulb then a $150 transformer.
Variac, or variable autotransformer, is a device to vary the output voltage from a steady AC input voltage (wall outlet voltage). It can maintain a steady voltage during a wide range of load conditions, allowing for very smooth variable control of voltage.
















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