- Which type of output has the Raspberry pi 3 model B: sinking or sourcing?
- I want to connect SSR (Omron G3MB-202P) to Raspberry GPIO. This SSR has one NO contact (NO means "normally opened", i.e. it closes on high (3.3-5V) voltage). Can I use such a schema to provide high voltage on SSR when GPIO is closed (set 0) and low voltage on SSR when GPIO is opened (set 1):
You could program the GPIOs to be sourcing or sinking. This depends on how you want your SSR relay to act.
If your question was about the default state of GPIOs, certain GPIO pins on Raspberry Pi are high when power is applied to the Pi and others are low by default.
About 2) I doubt you can reverse your signal with this shematic.
If you want to swap these values in an electronic manner, you will need a NOT logic gate. This gate can be a specific chip, or can be made with a single transistor, using this kind of shematic : as described here : http://www.electronics-tutorials.ws/logic/logic_4.html Other implementation can be found here : https://en.wikipedia.org/wiki/Inverter_(logic_gate)
Note : it may be easier to revert this signal directly in the code, rather than soldering extra components ;)
The Pi GPIO can "source" when high or "sink" when low. This is default setting. The GPIO can safely source or sink 16mA.
GPIO are NOT relays, and "open" or "closed" are meaningless concepts.
In addition GPIO can have a pull-up or pull-down. This is a high value resistor ~50kΩ - most have pull-up by default see http://www.panu.it/raspberry/ . This can be disabled if not wanted e.g. if driving high impedance circuitry, but is only relevant if the GPIO is configured as an input.
No amount of fiddling with resistors is going to change the logic state, but I do not see why you would want to do this, just invert logic in your code.
It is also unclear from your question what you intend to control with the SSR. Are you aware that these are only suitable for AC loads?