Controls current to platinum-wire filament. When pulling glass pipettes it is important that the current to the filament increase linearly with time in a repeatable manner. Therefore, we use a regulated power supply that delivers a current ramp from 0 amps up to an adjustable maximum current, Imax, in a preset time. The value of Imax is adjustable with a trimmer inside the box so that the filament reaches sufficient temperature to melt glass but not enough to melt the platinum filament. The ramp speed can be adjustabled by the user with a 10-turn pot and counting dial to give different ramp times between 6 and 60 seconds (0 -to- Imax). Electronic parts are not all listed below. See schematic diagram for additional parts. Also consider perhaps replacing all transformers, diodes, voltage regulators in that circuit with a single 3-output switching power supply such as Astec LPT43 .