Hi - I'm using a 7555 CMOS timer as an astable, driving a 2N3906 transistor, which in turn is switching a mobile phone vibration motor on for a short burst of a few seconds, and then back off for several minutes. I have this working nicely.
The motor is a tiny linear resonant actuator (LRA) about 10mm across and 3mm thick and consumes about 60mA. Voltage across it is around 3V DC.
If I was driving a small relay in a circuit like this, I'd put a freewheel diode across it.
My question is do I need to do the same with an LRA - where I don't quite understand how it operates and whether back EMF is an issue.
My working assumption is its like a tiny solenoid with a return spring, which breaks its own circuit as soon as the armature moves, so I'm thinking there could be some back emf there for a fraction of a second, but the field is going to be much smaller than a relay or motor.
Thoughts appreciated. Thanks!
The motor is a tiny linear resonant actuator (LRA) about 10mm across and 3mm thick and consumes about 60mA. Voltage across it is around 3V DC.
If I was driving a small relay in a circuit like this, I'd put a freewheel diode across it.
My question is do I need to do the same with an LRA - where I don't quite understand how it operates and whether back EMF is an issue.
My working assumption is its like a tiny solenoid with a return spring, which breaks its own circuit as soon as the armature moves, so I'm thinking there could be some back emf there for a fraction of a second, but the field is going to be much smaller than a relay or motor.
Thoughts appreciated. Thanks!