1. Protection Requirements

2. System Protection
System needs protection against harsh environments & extreme climates
Commercial grade components can operate between 0°C and 70°C. They can not be used in military equipment whose operating temperatures are between -40°C and +125°C.
Electric shock is another hazard and equipment chassis and controls need to be well grounded.
Protection against High temperature is thro air conditioning/fans internal or external.
EMI/EMC

3. CE marking
This is a European Union (EU) standard for safety. The CE marking certifies that a product may be brought into service only when it does not pose a risk to the health and safety of users
This safety requirement also applies if the device is used incorrectly.
CE marking is the manufacturer’s declaration that the product meets the requirements of the applicable EU directives

4. Surge Protection
Electronic gadgets are vulnerable to transient overvoltages, which can damage AND/OR reduce the equipment’s lifespan.
A transient overvoltage or surge is a short duration(micro or milli seconds) increase in voltage measured between two or more conductors.
These transients can cause premature ageing of equipment, downtime, or complete destruction of electronic components

5. Surge Protection
A strong lightning in the vicinity may leak through the cables and grounding and affect our appliances, such as TV, Fridge, computers

6. Surge Protection
These surges can go upto even 6 KV on 230 Vac power lines.
Surge arrestors should be in built in the design at the input wires. Spike busters do provide limited protection.
Transients can also be caused by other equipments - usually caused by the discharge of stored energy in inductive and capacitive components.
Electric motors used in elevators, air conditioning, refrigeration, can create 250V to 1000V transients.

7. Lightning Protector Circuit
The basic surge suppression circuit consists of a Voltage Dependent Resistor (VDR), in series with a Gas Discharge Tube (GDT) surge suppressor.
This combination is connected in shunt at the input of an equipment, for example between live and mains lead.
In a Telephone equipment, this surge protection circuit will be connected across the input copper lines. Under normal conditions, no current flows through GDT and VDR.

8. Lightning/Surge Protector Circuit
Whenever there is a surge/lightning, the GDT and VDR conduct, if the voltage across them exceeds the combined breakdown voltage of VDR+GDT.
The transient gets discharged across this protection circuit and does not proceed further towards the home appliance.
The VDR and GDT conducts as long as the transient condition persists. After that, VDR and GDT become open and normal working of the appliance is restored.