We have a circuit that is a 50kHz 'induction balance' metal detector. Two transmit coils that canel each other out and a receiver coil that picks up any disturbance in the canceled field. Winding the coils is difficult to get them exactly tuned and canceled. Is there an electrical component/circuit that can be added that will let us 'dial in' the fine tuning?
"Induction Balance" coil tuning
Jan 17, 2005
2 Replies
Yes. An RC network that has adjustable amplitude and phase shift would take a bit of the transmit signal and inject it into the receiver; you could then adjust for null.
John
well yes. a simple Pot between the 2 of them supplying the single to the coils. use the center tap as the feed from the OSC supply. the outer will connect to the coils.! 1 to each 1 leg of each coil. the remaining legs are tied together to the common.
i don't know the amount of current you are using but wire wound pots come in a variety of sizes. just use a low R Value... depending on how far off your coils are going to be will determine how wide of a range you need. you could also have 2 AMps driving the coils with a balance control. etc.
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required