Electronic/bench testing equipment and supplies simulate operating conditions and perform functional tests to see if devices are working correctly. Air ionizers and antistatic systems and supplies reduce static electricity to help ensure a safe environment for building and testing electronic devices. Bench, or benchtop, power supplies provide the correct voltages and currents to power circuits and devices when designing and troubleshooting equipment. Function generators produce precise signals with different types of electrical waveforms over a range of frequencies to help develop, test, and repair electronic equipment. Spectrum analyzers display the frequency spectrum and measure the channel power and occupied bandwidth of radio-frequency waves in cellular phones, radio transmitters, and radar systems.