Here's a schematic of a light-detection circuit. When light is shone on the circuit, it buzzes.
Having a look at this schematic, it seems most natural to me that the schematic should be drawn so that the LDR and the 390 should be on the middle 'branch' and the transistor and the buzzer should be on the leftmost 'branch'. The transistor stands in the way of the battery operating the buzzer.
Can schematics be drawn either way, or is there some sort of convention that I should know about?
Richard