Diodes and Resistors

Get the right components for the job with Frankies Auto Electrics' range of automotive diodes and resistors. Whether you're protecting circuits from back-feed voltage, isolating electrical systems or completing a professional auto electrical installation, our diodes are built to handle the demands of 12V and 24V automotive environments.

• 3 amp and 6 amp automotive diodes available in bulk packs
• Galvanic isolators for dual battery and marine electrical systems
• Trusted brands used by auto electricians across Australia
• Suitable for 12V and 24V vehicle applications
• Compact, reliable components for professional and DIY installs

Not sure which diode or isolator suits your application? Our NSW-based auto electrical team can point you in the right direction — contact us or visit in store.

Frequently Asked Questions

What is an automotive diode used for?

An automotive diode allows electrical current to flow in one direction only, preventing back-feed voltage from damaging sensitive components. They're commonly used in alarm and central locking installations, trailer wiring, and anywhere you need to isolate or protect a circuit from reverse current.

What amp rating diode do I need for my application?

The amp rating of a diode should match or exceed the current draw of the circuit it's protecting. A 3 amp diode suits low-current applications like alarm triggers and indicator feeds, while a 6 amp diode is better suited to higher-current circuits. If in doubt, our team can help you select the right rating.

What is a galvanic isolator and when do I need one?

A galvanic isolator prevents galvanic corrosion caused by stray electrical currents between dissimilar metals in marine or dual battery systems. It's commonly used in boats and caravans where shore power or multiple battery banks are connected, protecting fittings and hull components from electrochemical damage.

Can I use automotive diodes in a dual battery system?

Yes — diodes are often used in basic dual battery setups to prevent the auxiliary battery from discharging back into the main battery. However, for more efficient dual battery management, a dedicated isolator or DC-DC charger is generally recommended. Our team can advise on the best solution for your setup.

Does Frankies Auto Electrics offer auto electrical installation services?

Yes! Our experienced auto electricians across NSW can assist with circuit protection, dual battery systems, alarm installations and more. Contact us to discuss your project or book an installation today.