Damper

(a) A copper frame on which the wire in a galvanometer is sometimes coiled, which acts to damp the oscillations of the needle. (b) A tube of bra or copper placed between the primary and secondary coils of an induction coil. It cuts off induction and diminishes the current and potential of the secondary circuit. On pulling it out, the latter increases. It is used on medical coils to adjust their strength of action.