Build Your Own Current Limiter for Protection when Repairing and Testing Electronic Equipment

This video describes, in detail, how to construct a Current Limiting Device to protect you, your test equipment, and any electronic gear that you are testing or repairing. When used properly, it prevents short circuits from causing additional damage, particularly to expensive power transformers in amplifiers. It is also quite useful when first powering up previously untested and vintage equipment. It is not suitable for use with medium to large electric motors.

The bulb functions as a high-wattage resistor in which the resistance increases with the increasing heat of the filament. A "cold" bulb may offer only 2 or 3 ohms of resistance (the higher the wattage, the lower the resistance), but this will rapidly rise as the filament heats, particularly in the case of a short circuit.....protecting the circuit and dissipating the resulting filament heat in the form of light (warning you of the existence of the short).

IMPORTANT NOTE: The wattage of the bulb must be tailored to the current draw of the device being protected. The high-wattage bulbs (200W+) recommended in the video are primarily for Tube Amplifiers, which operate at relatively high current levels. With lower-current devices, such as Solid State amps, a lower wattage-higher resistance bulb (even as low as 40W) may be required for circuit protection.

Also, in my wiring diagram within the video, the "hot" AC lead is connected to the threaded socket of the receptacle, which could possibly be touched while changing bulbs. Some viewers have suggested that shock exposure could be reduced if the "hot" lead went to the contact at the bottom (center) of the socket. Please consider this when wiring your own Current Limiter.

The Photoflood Bulb used in this video is available on Amazon. Here is a link: http://www.amazon.com/Eiko-Supreme-Ph...

If you enjoy seeing videos featuring classic vintage jukeboxes and guitar amplifiers, please consider subscribing to my channel, to gain easy access to over 250 videos.....and to be notified when new videos are posted. Thanks for watching !!!