hi tom,
as i wrote in this thread, ready-to-plugin transformers are used
like them for telephones or similar home-used equipment ..they may
consist of a transformer and a rectifier (bridge-rectifier ?) i dont know
in addition i show my regulator - circuit
i like to use regulators even if a simple constant voltage is needed, because
the well-known LM7805 does spend more than 4,6 V, but Arduino runs better on 5V .
i have read that in forums and find out the same fact working here.
Another regulator I used in other cases is LM317(K), which is simpler
in circuit-design.
whats your experience with this ?