(71B) Basic Bridged-T Notch Filter - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Software Libraries (/forum-10.html) +--- Forum: General Software Library (/forum-13.html) +--- Thread: (71B) Basic Bridged-T Notch Filter (/thread-7464.html) (71B) Basic Bridged-T Notch Filter - Eddie W. Shore - 12-23-2016 07:24 PM Basic Bridged-T Notch Filter The program NOTCH calculates the required capacitor and resistor to null out an undesired frequency. Inputs: inductance (H), frequency to nullified (Hz), resistance of the required coil (Ω) Source: Rosenstein, Morton. Computing With the Scientific Calculator Casio: Tokyo, Japan. 1986. ISBN-10: 1124161430 Program NOTCH 244 Bytes, 12/22/2016 Code: ```10 DESTROY L,F,I,C,R 20 DISP “INDUCTANCE” @ WAIT 1 22 INPUT “in H: “; L 24 DISP “FREQUENCY” @ WAIT 1 26 INPUT “in Hz: “; F 28 DISP “COIL’S RESISTENCE” @ WAIT 1 30 INPUT “in Ω: “; I 40 C = 1/(2 * PI^2 * F^2 * L) 42 R = (PI * F * L)^2 / I 44 DISP “NOTCH CAPACITOR” @ WAIT 1 46 DISP C; “ F” @ PAUSE 48 DISP “NOTCH RESISTENCE” @ WAIT 1 50 DISP R; “ Ω”``` Notes: Capital Omega Character (Ω): [ g ], [RUN] (CTRL), [ Q ] Example: L = 0.12 H, F = 1170 Hz, Coil Resistance = 30 Ω Output: NOTCH CAPACITOR ≈ 3.08402 * 10^-7 F NOTCH RESISTENCE ≈ 6485.04070 Ω