Abstract: The invention is a current controller for use in, for example, automatic animal stunning equipment.A problem in the past has been that animal stunning equipment has not always stunned animals sufficiently humanely prior to slaughter. For example, when a short circuit has occurred and an animal is not sufficiently stunned, the animal has suffered trauma prior to slaughter. Regulations are now being introduced so as to minimise such trauma.The invention solves this problem by providing an improved Wilson mirror constant current generator which can operate in high voltage circuits, with good dynamic response, thereby ensuring the preferred current is always applied to correctly stun an animal.