Hello everyone,
Well i posted a similar circuit in another topic but a lot has changed in the design. So here is a brief story of what i am doing, actually i am in a project where i have to design a circuit which can be used to trigger solenoid valves for the airbags in the car, so i need a circuit with a time range of 0 to 1 seconds. Also the valves chosen are 12 V, 0.5 A and can go up to the maximum speed of 200 milisecond. In my group meeting it was decided to use a monostable 555 circuit to trigger valves as they need some sort of time regulation because it is something like that you press a button and an airbag go will off instantly and that car would be a demonstrator only!
So I have made a schematic for the monostable 555 circuit so four such circuits will be connected in parallel for the airbags,
this is the schematic for one circuit,
Also i have decided to use a variable resistor connected in series to regulate time,
**broken link removed**
so someone suggested me to modify the circuit above by plugging in this circuit below after the pin 3 which is output to protect the circuit.
**broken link removed**
so i am a little confused as can there be an alternative to the circuit above as it looks too complicated? I know i will need a diode connected in parallel to solenoid to prevent back emf but exactly don't understand why are transistors required? if transistors are required then what type of transistors do I use?
Also does this look achievable?
Waiting for replies!
Thank you
Well i posted a similar circuit in another topic but a lot has changed in the design. So here is a brief story of what i am doing, actually i am in a project where i have to design a circuit which can be used to trigger solenoid valves for the airbags in the car, so i need a circuit with a time range of 0 to 1 seconds. Also the valves chosen are 12 V, 0.5 A and can go up to the maximum speed of 200 milisecond. In my group meeting it was decided to use a monostable 555 circuit to trigger valves as they need some sort of time regulation because it is something like that you press a button and an airbag go will off instantly and that car would be a demonstrator only!
So I have made a schematic for the monostable 555 circuit so four such circuits will be connected in parallel for the airbags,
this is the schematic for one circuit,
Also i have decided to use a variable resistor connected in series to regulate time,
**broken link removed**
so someone suggested me to modify the circuit above by plugging in this circuit below after the pin 3 which is output to protect the circuit.
**broken link removed**
so i am a little confused as can there be an alternative to the circuit above as it looks too complicated? I know i will need a diode connected in parallel to solenoid to prevent back emf but exactly don't understand why are transistors required? if transistors are required then what type of transistors do I use?
Also does this look achievable?
Waiting for replies!
Thank you