Over-current is a situation where current flowing through a device is more than a particular limit. This leads the excess heat generation, risk of damage of device or fire.
What is over-voltage??
When a voltage higher than a particular limit exists across a device, this condition is knows as over-voltage. Depending on the duration over voltage can be a voltage spike or a permanent one leading to a hazardous situation. This may lead to a power surge.Here is a picture illustrating over-voltage:
What is over-power??
The collective effect of over-voltage and over-current is referred to as over-power.
I found a video on youtube that said Exploding electronic components.This is what happens when you connect things backwards with 30 Volts.
I found a video on youtube that said Exploding electronic components.This is what happens when you connect things backwards with 30 Volts.
So i jumped to watch the video and found it was very good, here's the video, have a look guys:
How to protect against over-current??
We can use FUSES, CIRCUIT BREAKERS, TEMPERATURE SENSORS AND CURRENT LIMITERS.
How to protect against over-voltage??
We can use a voltage regulator to provide a stable voltage and to reject surges.
Certain components are designed such that they don’t catch fire when exposed to over-current and over-voltage, examples for some of such components are given below:
(1)Resistors:
Blue coloured resistors don’t catch fire but may smoke at over-power. Yellow resistors may catch fire. So NEVER use them interchangeably.
(2)Electrolytic Capacitors:
Newer versions of capacitors have plus shaped vent(s) like things on top, so that at over-power these open up to release the electrolyte and toxic gases and don’t explode. The earlier capacitors didn’t have these so they would explode.
Here is a picture showing the vent(s):
(3)Transistors:
Some power transistors have a thermal shutdown feature.
(4)Voltage Regulators:
The new voltage regulators have a thermal shutdown feature.