Transformless power source for 24V relay. Resistors with 1mohm are placed for monitoring current and designing purposes. A circuit formed by a condenser and a resistor in paralel with relay contact protect contacts from sparks (corrosion) during off-switching (an idea from old telephone rotary dial). (later edit) That's not very good idea because the quiescent current through resistor (100K)and condenser(1uF) is about 2 mA.... I don't know...
24V zener diode must suport 300mA forward current
47 ohm resistor is rated at 3.5W minimum (5W)
