Relaxation oscillators are one of the applications of RC circuits. In a neon lamp oscillator circuit, while charging, the lamp acts as an open circuit. Once the voltage across the capacitor reaches a threshold value, the lamp acts like a short circuit, and the capacitor discharges, creating a bright flash. After discharging, the process repeats, and the time interval between the flashes is controlled by tuning the R and C values. For this reason, they are used as timers for several applications. In intermittent windshield wipers, the variable resistor adjusts the frequency of the sweeps. On increasing the resistance, the RC time constant increases, resulting in a longer sweeping time. A pacemaker is used to correct abnormalities in the heart rhythm by sending electrical signals to the heart. The circuit consists of a battery, a capacitor, a computer-controlled switch that flips to charge and discharge the capacitor, and a sensor that senses physical activity and breathing. The RC timer circuit controls the time period between the electrical signals sent to the heart based on feedback from the sensor.