Hi
Let me confess I am not an electrical wiz - on the contrary I build things I think will work based on what I have read.
Having built lots of power supplies in the past I thought a new one to drive a pyrography pen would be simple - just a supply to give between 1 and 2 volts at a current of between 1 and 4 amps.
Pyrography is when you decorate wood or leather by burning it (hopefully artistically) so the pyrography pen is basically a zero ohms filament.
Actually the cold resistance is between 0.05 and 0.1 ohms and hot resistance is not much more.
The problem is that all the devices I have looked at like the LM317K and LM338K have short circuit protection built in and I cannot find a datasheet which mentions loads with very low resistance. Pen 'nib' temperature needs to be controlled - I suspect by controlling the current.
This cannot be a new problem - has anyone got a tested design that might meet my requirements - I do not want to admit defeat and spend £100 buying one !
thanks
Ralph
Let me confess I am not an electrical wiz - on the contrary I build things I think will work based on what I have read.
Having built lots of power supplies in the past I thought a new one to drive a pyrography pen would be simple - just a supply to give between 1 and 2 volts at a current of between 1 and 4 amps.
Pyrography is when you decorate wood or leather by burning it (hopefully artistically) so the pyrography pen is basically a zero ohms filament.
Actually the cold resistance is between 0.05 and 0.1 ohms and hot resistance is not much more.
The problem is that all the devices I have looked at like the LM317K and LM338K have short circuit protection built in and I cannot find a datasheet which mentions loads with very low resistance. Pen 'nib' temperature needs to be controlled - I suspect by controlling the current.
This cannot be a new problem - has anyone got a tested design that might meet my requirements - I do not want to admit defeat and spend £100 buying one !
thanks
Ralph