Vcc | +------+ | __|__ Relay /^\ Diode 1N4002 Coil /---\ | | +------+ | Diode | / 1N4148 4.7K B |/ C parallel >-|>|-+--\/\/\/--| NPN Transistor: BC547A or 2N2222A port data | |\ E pin +-|<|-+ | V 1N4148 | | parallel >-----------+------+ port ground | Ground