Has anyone built this LC meter? The meter uses the PIC16F628.
http://ironbark.bendigo.latrobe.edu.au/~rice/lc/index2.html
I want to change the relay out with a FET. I read through the code and to me it looks like an N-FET low side should do the trick. Here is a code snip that makes me think I could use an N-FET.
To me this looks like setting portb, 7 high turns the relay on, and clearing it turns it off.
But when I read the FAQ there is this.
http://ironbark.bendigo.latrobe.edu.au/~rice/lc/faq.html
"Can I replace the relay with a 2N7000 FET?"
"This should be possible (with a "slight" change to the program to invert the control signal and a "slight" loss of accuracy).
I did try a NPN transistor in an early version of the prototype, but wasn't happy with the stability. This was probably due mainly to my "rat's nest" construction. My excuse for using a relay is pure laziness - having got it working, I wasn't going to mess with it."
Hence my confusion.
This may refer to older design where he uses a PNP to control the relay?
http://ironbark.bendigo.latrobe.edu.au/~rice/lc/index2.html
I want to change the relay out with a FET. I read through the code and to me it looks like an N-FET low side should do the trick. Here is a code snip that makes me think I could use an N-FET.
Rich (BB code):
#define relay PORTB,7 ; Switches Ccal
bcf relay ; Remove Ccal
and another putting Ccal in the circuit.
bsf relay ; Add standard capacitorBut when I read the FAQ there is this.
http://ironbark.bendigo.latrobe.edu.au/~rice/lc/faq.html
"Can I replace the relay with a 2N7000 FET?"
"This should be possible (with a "slight" change to the program to invert the control signal and a "slight" loss of accuracy).
I did try a NPN transistor in an early version of the prototype, but wasn't happy with the stability. This was probably due mainly to my "rat's nest" construction. My excuse for using a relay is pure laziness - having got it working, I wasn't going to mess with it."
Hence my confusion.
This may refer to older design where he uses a PNP to control the relay?
