Microphones have an electrical characteristic called impedance, measured in ohms (Ω), that depends on the design. In passive microphones, this value relates to the impedance of the coil (or similar mechanism). In active microphones, this value describes the load impedance for which its amplifier circuitry is designed. Typically, the "rated impedance" is stated. Low impedance is considered under 600 Ω. Medium impedance is considered between 600 Ω and 10 kΩ. High impedance is above 10 kΩ. Owing to their built-in amplifier, condenser microphones typically have an output impedance between 50 and 200 Ω.