02-10-2023, 05:03 PM
A barretter is usually iron wire in hydrogen. The closest off the shelf may be a tungsten lamp of suitable resistance, though halogen types have a better characteristic. Few thermistors are suitable and most have the opposite characteristic. The barretter is usually an approximation to a current limiter as resistance rises sharply with increasing current. Most thermistors are designed to be the reverse to limit power on inrush current on either series filaments or SMPSUs. A halogen lamp is a bit more than double resistance from cold to full power and a regular tungsten lamp (nitrogen filled not vacuum) maybe a bit less than double, I forget. Maybe some low power festoon lamps use a vacuum and will be more like a direct valve filament in resistance change.
