two important attributes of a radio receiver are "sensitivity" and "selectivity". the regenerative detector provides sensitivity and selectivity due to voltage amplification and the characteristics of a resonant circuit consisting of inductance and capacitance. the regenerative voltage amplification formula_1 is formula_2 where formula_3 is the non-regenerative amplification and formula_4 is the portion of the output signal fed back to the l2 c2 circuit. as formula_5 becomes smaller the amplification increases. the formula_6 of the tuned circuit (l2 c2) without regeneration is formula_7 where formula_8 is the reactance of the coil and formula_9 represents the total dissipative loss of the tuned circuit. the positive feedback compensates the energy loss caused by formula_9, so it may be viewed as introducing a negative resistance formula_11 to the tuned circuit. the formula_6 of the tuned circuit with regeneration is formula_13. the regeneration increases the formula_6. oscillation begins when formula_15.