Car audio electronic components
Car audio electronic components consist of many parts. They include . . .
• Diode - A diode allows current to pass in one direction. They are very useful in isolating current flow. They are often used in automotive security systems as well.
• LEDS - A LED is a special diode. LED stands for light-emitting diode. You are probably familiar with these as they are commonly used as turn on indicators for most electronic equipment too.
• Relay- A relay is an electro mechanical switch. It is most widely used for car security systems. It is also commonly used as a way of protecting your head unit from damage. Normally a relay allows a small current to control a much larger current.
A little more on relays
A relay consists of four main parts . . .
1. A coil denoted by terminals 85 and 86.
2. A common terminal denoted by terminal 30.
3. A normally closed terminal that is labeled terminal 87
4. And a normally open terminal labeled terminal 87.
Depending on whether your controlling voltage is negative or positive, the terminal 85 or 86 will be grounded or connected to +12 volts. If you have a positive controlling voltage like a head unit remote turn-on lead, then you will need to ground either terminal 85 or 86.
It does not matter which one you choose, the other terminal will be connected to the remote turn-on lead of your head unit. The common lead that is terminal 30 would be connected to +12 volts because that is what we want to apply to terminal 87 when the relay coil is energized.
