Hi everyone I stumbled across this forum and i can't believe i have never had this forum in my favourite before! Would have been so handy in earlier projects haha anyway this is my first post.
Just thought id ask the quick question about a frequency switch circuit.
I managed to pick up a "Shift light" that connects to a tacho signal wire and when the rpm reaches a certain level the led comes on.
I was going to make this circuit myself but without the use of the led and use a transistor to open a relay.
I can buy the shift light circuit made for $30 from aus or $18 from china so i don't think that part is worth me making.
Here is the info and on the items and my question:
The led that is on the circuit at the moment has 3v powering it when the desired rpm is reached. That bit is fine but off this led i want to control a transistor to then open the 12v relay.
The question i am having is what transistor do i need specifically i'm assuming an NPN would be most applicable for what i'm doing then just have the 12v +ve to the relay -ve from relay to the collector then from emitter to the 12v -ve
If i am wrong please do let me know.
Also will the transistors base need a +ve supply i'm guessing? so the +Ve on the led to a resistor of some kind then to the base on the transistor?
Any help would be greatly appreciated cheers
Just thought id ask the quick question about a frequency switch circuit.
I managed to pick up a "Shift light" that connects to a tacho signal wire and when the rpm reaches a certain level the led comes on.
I was going to make this circuit myself but without the use of the led and use a transistor to open a relay.
I can buy the shift light circuit made for $30 from aus or $18 from china so i don't think that part is worth me making.
Here is the info and on the items and my question:
The led that is on the circuit at the moment has 3v powering it when the desired rpm is reached. That bit is fine but off this led i want to control a transistor to then open the 12v relay.
The question i am having is what transistor do i need specifically i'm assuming an NPN would be most applicable for what i'm doing then just have the 12v +ve to the relay -ve from relay to the collector then from emitter to the 12v -ve
If i am wrong please do let me know.
Also will the transistors base need a +ve supply i'm guessing? so the +Ve on the led to a resistor of some kind then to the base on the transistor?
Any help would be greatly appreciated cheers