Phantom power

Phantom power - simultaneous transmission of dc power and information signals over one wire.

Content

• 1B sound recordings
• 2B computer networks
• 3B security technology
• 4Fire alarm
• 5V active broadcast TV antennas
• 6v cable tv
• 7V measuring equipment

In sound recording

Phantom power electret microphone

Most often used when connecting condenser microphones.

Phantom power sources are often built into mixing consoles, mic preamps and similar equipment. In traditional condenser microphones, phantom power is used not only to power the microphone circuit, but also for polarization. Microphones that require phantom power are most often connected today using an XLR connector.

The advantage of this scheme is to save copper, but in practice there are some difficulties. If the microphone input is connected to an unbalanced signal source, inadvertently turning on the phantom power may cause the device to fail, since it will be supplied with 48V negative effects.) Also when working with devices that require phantom power (for example, condenser microphones or direct boxes), you should always remember that yklyuchat device on the network should be closed only when the channel signal path. Otherwise, a strong pulse will give a voltage surge at the output.

In computer networks

Power over ethernet
	Typical power connections

Powering devices connected to Ethernet networks (IP cameras, access points, IP phones, etc.) is described by the IEEE 802.3af standard.

In security technology

Digital two-contact electronic keys ibutton with 1-Wire protocol, which are widely used in intercoms.

Fire alarm

Current consuming detectors can be powered via a loop. For conventional detectors, fire signal transmission is transmitted by increasing current consumption. Address detectors transmit a coded signal along the same loop through which they receive power.

In active broadcasting antennas

Coaxial cable connected to the receiving antenna and receiver (TV). The signal from the antenna reaches the receiver at the same time as the power supply of the low-noise amplifier built into the antenna is fed from the receiver.

In cable television

Phantom power over the trunk cable is used for remote backup power supply of the trunk and sub-main amplifiers.

In measurement technology

Phantom power of various sensors is widespread. There are sensors with a voltage output, but the most common analog current loop. In this case, the sensor consumes a current from the device, which varies in the range from 4 mA to 20 mA, depending on the signal size.