Electronic – Relay alternatives that are silent and support 500mA+


What can I use as a silent "general-purpose" relay alternative?

There are various scenarios where I will need a relay-like device that allows me to control one circuit with a separate isolated circuit.
I have 3.3-5V microcontrollers and I want to use them to control, say…

A 12V DC 1A circuit (large-ish current)
A button on a radio (low-voltage and current)
A 24V AC circuit

A simple 5V magnetic relay+diode+transistor would work for nearly any situation (and no calculations necessary), but they are too loud.
I see two alternatives: Optocouplers and solid state relays. Unfortunately, most of them seem to have a maximum output of around 50mA (I generally need 500mA or more). They are also harder to find and more expensive. Finally, they are not a simple coil and contact setup, and there is much less documentation on how to implement them with a microcontroller.

Are optocouplers and solid state relays the best solution? I'm looking at these:

Best Answer

A reed relay should solve all of your problems.