Sense (electronics)
Encyclopedia
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 intended 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 output is measured. In local sense, the supply simply measures the voltage at its output terminals
, where the leads
to the load connect. This method has the problem of not accounting for the voltage drop due to resistance
of the leads, which is proportional to the amount of current
drawn by the load. That is, the supply might be producing the correct voltage at its output terminals, but there will be a lower voltage at the input terminals of the load.
When this might cause a problem, remote sense can be used to force the power supply to counteract the voltage drop by raising the voltage at its output terminals. If successful, it will exactly cancel the drop along the leads, yielding the correct voltage at the input terminals of the load. This is accomplished by using separate "sense leads," connected to the load's input terminals, to measure the output voltage. (Because the sensing function draws only a very small amount of current, there is practically no additional voltage drop due to the sense leads themselves.)
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.
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
, sense is a technique used in power supplies
Power supply
A power supply is a device that supplies electrical energy to one or more electric loads. The term is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy to electrical energy...
to produce the correct voltage
Voltage
Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...
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
Feedback
Feedback describes the situation when output from an event or phenomenon in the past will influence an occurrence or occurrences of the same Feedback describes the situation when output from (or information about the result of) an event or phenomenon in the past will influence an occurrence or...
system to make adjustments based on the difference between its intended 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 output is measured. In local sense, the supply simply measures the voltage at its output terminals
Terminal (electronics)
A terminal is the point at which a conductor from an electrical component, device or network comes to an end and provides a point of connection to external circuits. A terminal may simply be the end of a wire or it may be fitted with a connector or fastener...
, where the leads
Lead (electronics)
In electronics, a lead is an electrical connection consisting of a length of wire or soldering pad that comes from a device. Leads are used for physical support, to transfer power, to probe circuits , and to transmit information...
to the load connect. This method has the problem of not accounting for the voltage drop due to resistance
Ohm's law
Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points...
of the leads, which is proportional to the amount of current
Electric current
Electric current is a flow of electric charge through a medium.This charge is typically carried by moving electrons in a conductor such as wire...
drawn by the load. That is, the supply might be producing the correct voltage at its output terminals, but there will be a lower voltage at the input terminals of the load.
When this might cause a problem, remote sense can be used to force the power supply to counteract the voltage drop by raising the voltage at its output terminals. If successful, it will exactly cancel the drop along the leads, yielding the correct voltage at the input terminals of the load. This is accomplished by using separate "sense leads," connected to the load's input terminals, to measure the output voltage. (Because the sensing function draws only a very small amount of current, there is practically no additional voltage drop due to the sense leads themselves.)
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.