Complex sentence: VCRs, in turn, react to these excessive voltage pulses by compensating with their automatic gain control circuitry, causing the recorded picture to wildly change brightness, rendering it annoying to watch.
Split into simpler sentences: VCRs, in turn, react to these excessive voltage pulses by compensating with their automatic gain control circuitry. This causes the recorded picture to wildly change brightness, rendering it annoying to watch.