The DM 501 Digital Multimeter measures DC and AC voltage and current, resistance and temperature. The AC functions respond to average values, and display RMS values. A single front-panel control selects all functions and ranges. A push button selects front panel input or rear interface connector input. Temperature measurements are made using a TEKTRONIX P6058 Probe (Part No. 010-0260-00) or other suitable sensing devices. Option 1 instruments are shipped without the P6058 probe. Front- panel pin jacks provide external temperature readout, independent of the function being displayed. An internal switch selects degrees calibration in either Centigrade or Fahrenheit. Option 2 instruments delete the temperature measuring capability. The readout is a 4 1/2-digit stored display using seven- segment LED's. The decimal point is automatically positioned by the RANGE/FUNCTION switch and leading zeros (those to the left of the decimal point or most significant digit) are blanked. Polarity indication is automatic. A blinking display indicates overrange. Serial BCD output is available at the rear interface connector.