Driving Relay with 555 IC
This is a Driving Relay circuit using 555 IC. The circuit is used to drive a relay to avoid 555 hangs up, it uses an inductive feedback. The coil is prevented to drive Pin 3 below a negative 0.6V by a clamp diode that across the coil. However, in some case, this negative voltage maybe cause the timer to malfunction. We can solve this problem by driving the relay through a dioda. So, pin 3 will never receives a negative voltage. Here is the circuit :
[Source: Philips Semiconductors Application Note]