By how much will the use of headphones increase battery life?
Since the speakers in most detectors are of 8 or 16 ohms impedance, while most detectors use a resistor of approximately 100 to 200 ohms to limit the sound output in the headphones, the current necessary to drive a set of headphones is considerably smaller than that required to drive the low impedance speaker. Using the figures just given, a set of headphones would increase battery life by 2 or 3 times. However, since the electronic circuitry in the detector is always operating when the machine is switched on, even though the detector may not be making any noises, the savings on battery life may not be as big as the above numbers seem to indicate.
Since the speakers in most detectors are of 8 or 16 ohms impedance, while most detectors use a resistor of approximately 100 to 200 ohms to limit the sound output in the headphones, the current necessary to drive a set of headphones is considerably smaller than that required to drive the low impedance speaker. Using the figures just given, a set of headphones would increase battery life by 2 or 3 times. However, since the electronic circuitry in the detector is always operating when the machine is switched on, even though the detector may not be making any noises, the savings on battery life may not be as big as the above numbers seem to indicate.
