A symmetrical lateral bipolar junction transistor (SLBJT) is provided. The SLBJT includes a p-type semiconductor substrate, a n-type well, an emitter of a SLBJT situated in the n-type well, a base of the SLBJT situated in the n-type well and spaced from the emitter by a distance on one side of the base, a collector of the SLBJT situated in the n-type well and spaced from the base by the distance on an opposite side of the base, and an electrical connection to the substrate outside the n-type well. The SLBJT is used to characterize a transistor in a circuit by electrically coupling the SLBJT to a gate of the test transistor, applying a voltage to the gate, and characterizing aspect(s) of the test transistor under the applied voltage. The SLBJT protects the gate against damage to the gate dielectric.