Precision metal film MELF resistors  HPMRY provides a combination of high precision and tolerance to surge conditions, the resistors are ideal for measuring supply line voltage levels in energy metering and power condition monitoring.
 
The HPMRY74M and HPMRY16M are rated at 0.4 and 1W respectively. The former specifies a maximum 5 second overload voltage of 400V and the latter, 700V. Standard values from 10R to 1M0 are available in E24 and E96 ranges, giving plenty of scope for ‘close value match’ choice to designers.  A wide ambient temperature range of -55 to 155℃ is accommodated.

 
The resistors’ excellent surge tolerance characteristics enhance reliability and reduce field failures.  With precision levels of +/-0.1% resistance tolerance and +/-15ppm/℃ TCR, they free up designers’ error budgets, enabling savings elsewhere in the circuit. 
 
Physically the resistors comprise a homogeneous sputtered metal alloy film on a high-grade ceramic rod. The resistance is adjusted to final value by a helical laser cut in the film, and the resistor body is protected by a lacquer coating. The resistors’ end caps’ pure tin finish comprise ageing free contacts onto which low melting-point solders can be used. HPMRY74M resistors measure 3.5 length x 1.3 diameter, and the HPMRY16M, 6.0x 2.1mm. 
 Aimed at industrial, instrumentation and automotive applications, the resistors  find favour with designers of energy meters, measurement instruments, process monitors and automotive control systems. Driving the demand for this type of product is the growth in smart meters for billing and for site or process energy management, and also the demand for higher reliability automotive grade components. Microhm Electronics’ HPMRY range of precision metal film resistors provides a leading combination of precision, high power rating and tolerance to surges.