The Philips recorders PM 8041, PM 8131 and PM 8141 are multirange X-Y recorders, suitable for a wide variety of applications where the relationship of two variables y = f (x) has to be recorded. The STANDARD A4 version PM 8041 is a low-cost recorder for routine applications with a multirange unit with calibrated sensitivities from 2 mV/cm to 1 V/cm; variable adjustment provides over-lapping between ranges and zero positioning over the complete recording area. The MULTIPURPOSE A4 version PM 8141 and the SINGLE PEN A3 version PM 8131 are recorders for applications in research, development and education. Both of these recorders extend the flexibility by offering a multi-range unit with 14 calibrated sensitivities from 0,05 mV/cm to 1 V/cm and a separate zero suppression switch; which allows calibrated zero suppression up to 400 %. Common features for the above mentioned types are: - strong but lightweight frame casting which facilitates simple rack mounting - low temperature drift - high sensitivity and accuracy - high pen acceleration and writing speed - electrostatic chart hold down - simple and accurate chart alignment - mechanical and electronic overload protection for the servo motor - disposable nylon pen cartridges for reliable writing - roll chart of 15 m recording length for the A4 recorders, which is perforated to an A4 format for easy tear off. - high rejection of interference signals - zero positioning over the complete recording area - remote control facility for pen lift and for the time base functions start and reset. On all recorders the automatic time-base module PM 9884 can be easily inserted. The time function can be switched to either X or Y axis. Five sweep speeds are selectable from 0,5 to 10 s/cm. The sweep can be interrupted by means of a reset switch during recording. Note: This operation manual should be studied carefully in order to obtain optimum utilisation of the recorder facilities.