bananasiong
New Member
Hi,
For an example, a FM transmitter, why does the coil need to be hand made but not the inductor? Is it because of the inductor consists of a coil and a resistor in series and a capacitor in parallel with them (I found this inductor equivalent circuit from the reference book)? I've made a FM transmitter, by calculation, the inductance of the coil is around 760 nH. It works with a 33 pF trimmer capacitor. In order to get the FM band, the inductance of the tank has to be around 76 nH. Is it because of the stray capacitance and inductance? So for designing such circuit, we have to reduce the value of the L and C for an expected frequency?
Since the frequency is inverse proportional to the product of LC, by increasing the L, is the quality, Q also increased?
I'm still learning RF oscillator from a reference book, but I can't figure out why a RFC is needed as the load of the collector or the drain of bjt or fet for Colpitts and Hartley oscillator.
I've seen a power supply design with additional of RC filter between the main filter capacitor and the load to reduce the ripple. Will the limitation of the load current be reduced?
Thanks
For an example, a FM transmitter, why does the coil need to be hand made but not the inductor? Is it because of the inductor consists of a coil and a resistor in series and a capacitor in parallel with them (I found this inductor equivalent circuit from the reference book)? I've made a FM transmitter, by calculation, the inductance of the coil is around 760 nH. It works with a 33 pF trimmer capacitor. In order to get the FM band, the inductance of the tank has to be around 76 nH. Is it because of the stray capacitance and inductance? So for designing such circuit, we have to reduce the value of the L and C for an expected frequency?
Since the frequency is inverse proportional to the product of LC, by increasing the L, is the quality, Q also increased?
I'm still learning RF oscillator from a reference book, but I can't figure out why a RFC is needed as the load of the collector or the drain of bjt or fet for Colpitts and Hartley oscillator.
I've seen a power supply design with additional of RC filter between the main filter capacitor and the load to reduce the ripple. Will the limitation of the load current be reduced?
Thanks