Sense (electronics)

In electronics, sense is a technique used in power supplies to produce the correct voltage for a load. Although simple batteries naturally maintain a steady voltage (except in cases of large internal impedance), a power supply must use a feedback system to make adjustments based on the difference between its goal output and its actual output. If this system is working, the latter will be very close to the former.

Two types of sense are used, depending on where the power supply measures its performance. In local sense, the supply simply measures the voltage on its output terminals, where the leads from the load connect. This method has the problem of sometimes resulting in a voltage drop across the leads. That is, the supply might be producing the correct voltage on its output terminals, but there may be a much lower voltage on the input terminals of the load.

In such situations, remote sense can be used to force the power supply to counteract the voltage drop by raising the voltage on its output terminals. If successful, it will exactly cancel the drop along the leads, yielding the correct voltage on the input terminals of the load. In general, there are separate leads for a remote sense system which connect to the load's input terminals (and also possible to a resistor and capacitor in parallel). On the other hand, local sense is purely internal and requires no separate leads.

Many power supplies that are equipped with remote sense can suffer catastrophic damage if turned on while the sense leads are unconnected. To avoid this, some supplies are equipped with auto sense, which will automatically switch between local and remote sensing depending on whether the sense leads are correctly connected.

ee also

* Sensor

External links

* [http://www.power-one.com/technical/remote.html Power-One]
* [http://www.nasatech.com/Briefs/Sept02/KI0902.html NasaTech]