C APPENDIX INSTRUMENTS USED IN THE PHYSICS 321 LABORATORY The instruments we use in the laboratory provide or measure DC and AC voltages and/or currents. The tables below list the specifications for devices actually used in the Physics 321 Laboratory. These tables are followed by a discussion of the general properties of instruments which provide these functions. SUBSTITUTION OR DECADE BOXES RESISTANCE General Radio Eico Heathkit Substitution Box Heathkit Decade Box CAPACITANCE Eico INDUCTANCE General Radio ACCURACY 0.05 % 0.5 % 10 % 0.5 % 1%
1%
DC POWER SUPPLY - Lambda Model LPD-421FM Floating Output Maximum Voltage Maximum Current Polarity Voltage Regulation Outputs can be at 300V off ground 20 V 1.7 A Either positive or negative terminal can be grounded 0.01% + l mV for line voltage 105 to 132 VRMS 0.01% + l mV for 0 to 1.7A load current Current Regulation 5 mA for line voltage 105 to 132 VRMS 5 mA for 0 to 20V output voltage Ripple and Noise 500 VRMS h (0.015 % + 0.5mV)/C Voltage Temperature Coefficient
FUNCTION GENERATOR - Wavetek Model 180 Floating Output Maximum Voltage Ground need not be at either output terminal HI output: 20 Vpp into an open circuit 10 Vpp into a 50 ohm load LO output: 1 Vpp into a 50 ohm load TTL output: Square wave drives up to 20 TTL loads HI output: 5V into a 50 ohm load LO output: 1V into a 50 ohm load HI and LO output: 50 ohms TTL output is 3 NANDs ORed 0.1Hz to 2 MHz in 7 range steps sine, square, and triangle for HI and LO outputs time symmetry h 1% on all but 1 MHz range Typically h 0.5% for sine waves on all ranges square wave rise time < 75 ns triangle wave linearity > 99% up to 200 kHz
Voltage Offset Output Impedance Frequency range Waveform Distortion
VOLT-OHM-MILLIAMMETER (VOM) - Simpson Model 270 Floating Input Galvanometer DC Voltage Inputs can be 1kV off the case potential rg = 5000 (50 ohms A full scale) sensitivity = 20,000 ohms/V (50 A FS) ranges are 0 to 0.25, 2.5, 10, 50, 250, and 1000 V FS accuracy h h 1.75 % of reading sensitivity = 0.252 ohm-A (0.25 V FS) ranges are 50 A and 1, 10, 100, and 500 mA FS accuracy h 1.75% of reading sensitivity = 5,000 ohms/V (200 A FS) ranges are 0 to 0.25, 2.5, 10, 50, 250, and 1000V FS accuracy h 3.0% of reading for Vpp > 0.4 V average reading calibrated in sine wave RMS accuracy h 1.75 of arc ranges are Rx1 0 to 2 k 12 center Rx100 0 to 200 k 1200 center Rxl0,000 0 to 20 M 120 k center open circuit nominal output voltage: 1.5 V on Rx1 and Rx100 7.5 V on Rxl0,000 maximum output current: l60 mA on Rx1 1.3 mA on Rx100 0.3 mA on Rxl0,000
DC Current
AC Voltage
DC Resistance
DIGITAL MULTIMETER (DMM) - Keithley Model 175 & 178 Model 175 DC Voltage: Ranges (volts FS) Input impedance Accuracy AC Voltage: Ranges (volts FS) Input impedance Accuracy (f < 20kHz) DC Resistance Ranges Accuracy Current 0.2, 2, 20, 200, 1000 10 M or 11 M (depending on range) h (0.03 % + 1 digit) True RMS 0.2, 2, 20, 200, 750 10 M or 11 M shunted by <...