For proper operation of electronic devices, current should be well controlled. Leakage current is due to minority charge carrier, or it is an unwanted current in the device. What is the on current and off current? How is the off current different from the leakage current and what is the significance of the off current?
Dear CAolleagues,
This topic is interesting.
Any switch including the electronic devices working as switches has two sates the off sate and the on state. The ideal switch is taken as reference for to compare switches. The ideal switch has the following performance:
The off resistance is infinity, or the off current is equal to zero.
The on resistance is eqaul to zero
and the switching times ton =toff=0
Such switch is not existing in the reality,
real switches have normally very small off current which some times called the leakage current with analogy to mechanical valves for fluids where when off they must cut off completely but it may be not firmly tight and leak fluids. Therefore it is called a leakage current. Leakage current may have different mechanisms in electronic devices. It may be due to volume conduction or surface conduction.
The on current is a unique terminology for the current flowing in the switch when it is on. Normally as the switch has very small on resistance, it must be limited by external circuit connected to the switch mostly the load resistance.
Best wishes
If you apply voltage to turn on a device, the current at the beginning when the device is in off state, is the off current. The current after the device is turned on is the on current and current flowing through the insulated path or the dielectric layer (in case of MOSFET, the gate current) is the leakage current.
Thanks Sanjib
According to you When the applied voltage is more than Threshold Voltage device is on, at this condition current following is called ON current.
2. Current follow in off state is called off current. can you tell me, what is the reason behind this. as I know this is due to minority charge carrier present in the device. and gate current due to interface charge present in oxide layer.
On current and off current are MOS channel (Ids) current, whereas Leakage current caused by leaks between the diffusion layers and the substrate.
Excerpt coped from book "characterization and modeling of digital circuits" available at www.paripath.com/book.
Dear CAolleagues,
This topic is interesting.
Any switch including the electronic devices working as switches has two sates the off sate and the on state. The ideal switch is taken as reference for to compare switches. The ideal switch has the following performance:
The off resistance is infinity, or the off current is equal to zero.
The on resistance is eqaul to zero
and the switching times ton =toff=0
Such switch is not existing in the reality,
real switches have normally very small off current which some times called the leakage current with analogy to mechanical valves for fluids where when off they must cut off completely but it may be not firmly tight and leak fluids. Therefore it is called a leakage current. Leakage current may have different mechanisms in electronic devices. It may be due to volume conduction or surface conduction.
The on current is a unique terminology for the current flowing in the switch when it is on. Normally as the switch has very small on resistance, it must be limited by external circuit connected to the switch mostly the load resistance.
Best wishes
ON CURRENT= the current after the threshold voltage by which electron movement takes place from source to drain
OFF CURRENT= the current below the threshold voltage ,,,and it changes(increasess) exponentially ,as vds increasess the off current increasses (exponentially)
LEAKAGE CURRENT=The current during off mode and by short channel effects,shrinking oxide effects,low channel (surface to volume ratio)
- Badges
- Science topic
- Similar topics
- Solid State Physics
- Devices