UIUC Physics 498POM
Physics of Music/Musical Instruments
Vacuum Tube Measurements

August 21, 2002:
We have recently upgraded/improved our PC-based Vacuum Tube Measurement DAQ system, which we use to obtain measurements of grid and plate family curves for e.g. 12A*7-type dual triodes and power tubes commonly used in guitar tube amps.

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Here is a pix of Prof. Errede running the Tube DAQ setup in the P498POM Lab:

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In the following, we show some results obtained with the PC-based tube measurement DAQ system:

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12A*7 Type Dual Triodes:

• Main Display Panel for TrioPar-5 Dual-Triode DAQ program (101 kb Jpeg file)

Grid Family Curves (n.b. 2 per plot, since dual triode):

• [3] Cathode Current, I_k vs. Grid Voltage, V_g for Grid Family Scan for NOS RCA 12AX7a (77 kb Jpeg file)

• [4] Grid Transconductance, g_m = 1/r_m = dI_k/dV_g(V_p = const) vs. Grid Voltage, V_g for Grid Family Scan for NOS RCA 12AX7a (90 kb Jpeg file)

• [5] Grid Transconductance, g_m = 1/r_m = dI_k/dV_g(V_p = const) vs. Cathode Current, I_k for Grid Family Scan for NOS RCA 12AX7a (91 kb Jpeg file)

• [6] Grid "Transimpedance", r_m = 1/g_m = dV_g/dI_k(V_p = const) vs. Grid Voltage, V_g for Grid Family Scan for NOS RCA 12AX7a (80 kb Jpeg file)

• [6] Log Grid "Transimpedance", r_m = 1/g_m = dV_g/dI_k(V_p = const) vs. Grid Voltage, V_g for Grid Family Scan for NOS RCA 12AX7a (100 kb Jpeg file)

• [7] Grid "Transimpedance", r_m = 1/g_m = dV_g/dI_k(V_p = const) vs. Cathode Current, I_k for Grid Family Scan for NOS RCA 12AX7a (78 kb Jpeg file)

• [7] Log Grid "Transimpedance", r_m = 1/g_m = dV_g/dI_k(V_p = const) vs. Cathode Current, I_k for Grid Family Scan for NOS RCA 12AX7a (100 kb Jpeg file)

• [8] Cathode Current, I_k vs. Thermionic Electron Kinetic Energy for Grid Family Scan for NOS RCA 12AX7a (99 kb Jpeg file)

• 3-D Surface for Grid Family Scan (I_k vs. Vgk for fixed values of Vpk) for NOS RCA 12AX7a (60 kb Jpeg file)

Plate Family Curves (n.b. 2 per plot, since dual triode):

• [3] Cathode Current, I_k vs. Plate Voltage, V_p for Plate Family Scan for NOS RCA 12AX7a (83 kb Jpeg file)

• [4] Child-Langmuir Law: Log Cathode Current, I_k vs. Log Plate Voltage, V_p for Plate Family Scan for NOS RCA 12AX7a (113 kb Jpeg file)

• [5] "Static Plate Conductance", g_s = 1/r_s = I_k/V_p(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS RCA 12AX7a (85 kb Jpeg file)

• [6] "Static Plate Conductance", g_s = 1/r_s = I_k/V_p(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS RCA 12AX7a (86 kb Jpeg file)

• [7] "Static Plate Resistance", r_s = 1/g_s = V_p/I_k(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS RCA 12AX7a (86 kb Jpeg file)

• [7] Log "Static Plate Resistance", r_s = 1/g_s = V_p/I_k(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS RCA 12AX7a (105 kb Jpeg file)

• [8] "Static Plate Resistance", r_s = 1/g_s = V_p/I_k(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS RCA 12AX7a (84 kb Jpeg file)

• [8] Log "Static Plate Resistance", r_s = 1/g_s = V_p/I_k(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS RCA 12AX7a (109 kb Jpeg file)

• [9] Dynamic Plate Conductance, g_p = 1/R_p = dI_k/dV_p(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS RCA 12AX7a (98 kb Jpeg file)

• [10] Dynamic Plate Conductance, g_p = 1/R_p = dI_k/dV_p(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS RCA 12AX7a (96 kb Jpeg file)

• [11] Dynamic Plate Resistance, R_p = 1/g_p = dV_p/dI_k(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS RCA 12AX7a (96 kb Jpeg file)

• [11] Log Dynamic Plate Resistance, R_p = 1/g_p = dV_p/dI_k(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS RCA 12AX7a (106 kb Jpeg file)

• [12] Dynamic Plate Resistance, R_p = 1/g_p = dV_p/dI_k(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS RCA 12AX7a (91 kb Jpeg file)

• [12] Log Dynamic Plate Resistance, R_p = 1/g_p = dV_p/dI_k(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS RCA 12AX7a (106 kb Jpeg file)

• 3-D Surface for Plate Family Scan (I_k vs. Vpk for fixed values of Vgk) for NOS RCA 12AX7a (60 kb Jpeg file)

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Power Tubes:

• Main Display Panel for PowerPar-1 Power Tube DAQ program (90 kb Jpeg file)

Grid Family Curves:

• [1] Cathode Current, I_k vs. Grid Voltage, V_g for Grid Family Scan for NOS JAN Philips 7581a (93 kb Jpeg file)

• [2] Grid Transconductance, g_m = 1/r_m = dI_k/dV_g(V_p = const) vs. Grid Voltage, V_g for Grid Family Scan for NOS JAN Philips 7581a (100 kb Jpeg file)

• [3] Grid Transconductance, g_m = 1/r_m = dI_k/dV_g(V_p = const) vs. Cathode Current, I_k for Grid Family Scan for NOS JAN Philips 7581a (99 kb Jpeg file)

• [4] Grid "Transimpedance", r_m = 1/g_m = dV_g/dI_k(V_p = const) vs. Grid Voltage, V_g for Grid Family Scan for NOS JAN Philips 7581a (95 kb Jpeg file)

• [5] Grid "Transimpedance", r_m = 1/g_m = dV_g/dI_k(V_p = const) vs. Cathode Current, I_k for Grid Family Scan for NOS JAN Philips 7581a (86 kb Jpeg file)

• [6] Cathode Current, I_k vs. Thermionic Electron Kinetic Energy for Grid Family Scan for NOS JAN Philips 7581a (102 kb Jpeg file)

• 3-D Surface for Grid Family Scan (I_k vs. Vgk for fixed values of Vpk) for NOS JAN Philips 7581a (60 kb Jpeg file)

Plate Family Curves:

• [1] Cathode Current, I_k vs. Plate Voltage, V_p for Plate Family Scan for NOS JAN Philips 7581a (90 kb Jpeg file)

• [2] Child-Langmuir Law: Log Cathode Current, I_k vs. Log Plate Voltage, V_p for Plate Family Scan for NOS JAN Philips 7581a (122 kb Jpeg file)

• [3] "Static Plate Conductance", g_s = 1/r_s = I_k/V_p(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS JAN Philips 7581a (100 kb Jpeg file)

• [4] "Static Plate Conductance", g_s = 1/r_s = I_k/V_p(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS JAN Philips 7581a (99 kb Jpeg file)

• [5] "Static Plate Resistance", r_s = 1/g_s = V_p/I_k(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS JAN Philips 7581a (95 kb Jpeg file)

• [6] "Static Plate Resistance", r_s = 1/g_s = V_p/I_k(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS JAN Philips 7581a (86 kb Jpeg file)

• [7] Dynamic Plate Conductance, g_p = 1/R_p = dI_k/dV_p(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS JAN Philips 7581a (103 kb Jpeg file)

• [8] Dynamic Plate Conductance, g_p = 1/R_p = dI_k/dV_p(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS JAN Philips 7581a (107 kb Jpeg file)

• [9] Dynamic Plate Resistance, R_p = 1/g_p = dV_p/dI_k(V_g = const) vs. Plate Voltage, V_p for Plate Family Scan for NOS JAN Philips 7581a (93 kb Jpeg file)

• [10] Dynamic Plate Resistance, R_p = 1/g_p = dV_p/dI_k(V_g = const) vs. Cathode Current, I_k for Plate Family Scan for NOS JAN Philips 7581a (83 kb Jpeg file)

• 3-D Surface for Plate Family Scan (I_k vs. Vpk for fixed values of Vgk) for NOS JAN Philips 7581a (65 kb Jpeg file)

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