Short circuit protection reverse polarity protection and over under voltage protection are some of the protection circuits that are used to protect any electronic appliance or circuit from any sudden mishappenings.
Over voltage protection circuit diagram.
All three techniques are used and can provide effective power supply over voltage protection.
Generally fuse or mcb is used for overvoltage protection however in this project our aim is to make a circuit which can perform better than a fuse or mcb and overcome the.
Overvoltage and under voltage protection circuit diagram.
Zener diode circuit for overvoltage protection.
The above circuit is designed to protect the circuit that connects to it from voltage over 13v.
As per datasheet tl431a is the three terminal programmable integrated circuit.
This zener diode circuit uses the zener diode in a slightly different way detecting the breakdown current through the diode once a certain voltage has been reached.
This circuit is a very useful auto cut circuit to the protection of any electrical or.
Load is connected with nc normally connected pin of the relay.
Overvoltage autocut circuit diagram this autocut circuit is very easy simple and very useful.
Overvoltage protection circuit using timers.
How the upper lower voltage works.
How 230v mains overvoltage protection circuit works.
Obviously this form of over voltage protection requires circuits that are specific to the particular circuit and switch mode power supply chips used.
The complete circuit diagram for our main over voltage protection is given below.
It is meant to use with 12v rated circuits devices.
Another form of zener diode circuit is an overvoltage protection circuit.
Over voltage protection circuit using tl431 shunt regulator ic.
To understand the basics of the overvoltage protection circuit let s take the circuit apart in order to understand the basic working principle of every.
Here is the basic schematics of the upper lower voltage circuit.
And when q2 is in off condition the base terminal of q1 will be low and it allows the current to flow through it.
When the voltage is less than the preset level the base terminal of the q2 is high and as it is a pnp transistor it turns off.
This is a shunt regulator diode.
Generally 12v devices will have a tolerance up to 13v.
Only one transistor and some other components are used in this overvoltage protection auto circuit.
Automatic equipment disconnect when the power cross the level of a fixed voltage.
The working of the circuit is discussed further below.
In the normal operating conditions between 160 and 250 v the output of the timer 1 is held low so the transistor 1 is in cutoff state as a result the reset pin of the timer 2 is high which causes to output at pin 3 is high so the transistor 2 conducts and then the relay coil gets energized.
Lm393 has 2 comparators.
So it will establish protection over 13v and moreover this will give the power supply necessary wiggle room to operate.
One of the comparators is sensing the higher voltage and another comparator is sensing the lower voltage.
Each has its own advantages and disadvantages and the choice of technique needs to be made dependent.
