Time delay activated and inertia activated are two types of brake controllers even though each type of controller has a specific function and purpose. Electric trailer brake controller is a device that supplies power from a tow vehicle to a trailer's brakes. While the controllers operate differently, they are very similar. Both types have the same wiring configuration.
Both allow the driver to adjust the amount of braking power and both have a pressure sensitive manual override switch that can be used to apply the trailer brakes independently of the tow vehicle. Time Delay Activated or "solid state" controllers are enabled by the depressing of the brake pedal in the tow vehicle. Once enabled, time delay activated controllers apply a gradual voltage to the trailer's brakes using a Time Delay Circuit. The advantages of a solid state brake control unit are the inexpensive cost, low profile, and they can be mounted at any angle. The disadvantages mostly pertain to Hazard Flashers issues. In most applications the digital display will flash with the hazard flashers and if the gain is set aggressively, some pulsing of the trailer brakes may be felt. Hazard Flasher issues can be resolved by using a Pulse Preventer that will isolate the brake control from the vehicles flashers, thus eliminating the pulsing. Inertia Activated Brake Controllers or Pendulum Style controllers are enabled by the depressing of the brake pedal and activated by a Pendulum Circuit that senses the stopping motion of the vehicle. The Pendulum Circuit applies a proportional voltage to the trailer's brakes. When the Inertia activated brake control is properly adjusted, the trailer will decelerate at the same speed as the towing vehicle. A result of this is increased braking efficiency and reduced wear on the brakes. Advantages of pendulum style controllers are efficient braking under a variety of braking conditions including adverse conditions. They also have a smooth braking motion. Pendulum style controllers have a few disadvantages also. They tend to be larger than solid state controller. They usually more expensive and they must be mounted in a level position. Tekonsha's Prodigy controller is an exception. Due to its innovative technology, it can be mounted in almost any position.
Hazard Flasher issues can be resolved by using a Pulse Preventer that will isolate the brake control from the vehicles flashers, thus eliminating the pulsing. Inertia Activated Brake Controllers or Pendulum Style controllers are enabled by the depressing of the brake pedal and activated by a Pendulum Circuit that senses the stopping motion of the vehicle.