Dear All,
I am trying to build up the circuit for vehicle detection using Collpits Oscillator (Inductive Loop). For that i have referred the circuit mention in figure. In this circuit L1 is get replaced by the inductive loop of size 4*8 Feet Having 5 Turns. The property of collpits that i am looking for , when metal comes closer to L1 (Inductive Loop) the frequency must need to change. While going through simulation part, as i am trying to change inductance value i.e L1 with value of 10 mH to 60 mH then frequency gets changed. It also proven by practical. Only the term change is inductive loop size. Loop size is small one 1*1.5 Feet.
As soon as metal get closer to that inductive loop, frequency gets changed and change in frequency get observed by using CRO. Now the query is, while connecting loop which having size of 4*8 then circuit didn't responds to frequency change. Please suggest suitable changes in schematic so that i can solve the issue. Ultimately goal is to design the circuit to detect vehicle presence on inductive loop.
I am trying to build up the circuit for vehicle detection using Collpits Oscillator (Inductive Loop). For that i have referred the circuit mention in figure. In this circuit L1 is get replaced by the inductive loop of size 4*8 Feet Having 5 Turns. The property of collpits that i am looking for , when metal comes closer to L1 (Inductive Loop) the frequency must need to change. While going through simulation part, as i am trying to change inductance value i.e L1 with value of 10 mH to 60 mH then frequency gets changed. It also proven by practical. Only the term change is inductive loop size. Loop size is small one 1*1.5 Feet.
As soon as metal get closer to that inductive loop, frequency gets changed and change in frequency get observed by using CRO. Now the query is, while connecting loop which having size of 4*8 then circuit didn't responds to frequency change. Please suggest suitable changes in schematic so that i can solve the issue. Ultimately goal is to design the circuit to detect vehicle presence on inductive loop.