# Setra Blog

Converting mA to voltage is common in HVAC when working with pressure transducers. Terminology to keep in mind includes:

• 1 mA = 0.001 AMP (short for amperes)
• Amps are referred to as CURRENT
• Resistor values are in OHMS (Ω is the symbol for ohms)
• VOLTAGE is the result of passing amps through a resistor

1. Pressure

The first and most important consideration is pressure. A number of questions must be answered to ensure the correct transducer is selected. What is the pressure range that the transducer will measure? What is the maximum pressure the transducer will encounter? What is the potential for over pressure in the system?

Pressure transducers today are more rugged and reliable than ever. Made of stainless steel construction, they provide abundant overpressure protection, improved total error band, and offer negligible orientation and vibration effects. They are ideal for long-term use even in harsh environments of extreme temperature, humidity, and vibration.

The accuracy of differential pressure transducers has greatly improved to provide better solutions for demanding applications. This article discusses why accuracy is an important consideration when selecting a pressure transducer for low-differential, critical pressure applications.

Total Error Band (TEB) is a measurement of worst case error; it is the most comprehensive and concise measurement of a sensors true accuracy over a compensated temperature range.  TEB is extremely important to know when trying to determine how well a sensor will work within a particular design system. By calculating TEB you'll be able to understand the different possibilities for error. Formulating TEB can be tricky if you don't have the right inputs readily available.

### Happy Halloween From Setra

Have you ever wanted to build your own Haunted House or Spooky Trail?

I'm sure we've all thought about it one time or another. You know what I'm talking about. Places like amusement parks, fairs, or even a homemade one that your “Halloween Crazed” neighbors down the street built themselves. But how do they work?

Absolute pressure is measured relative to a full vacuum (0 PSIA = 14.7 PSIV).  The electrical output of an absolute pressure transducer is 0 VDC at 0 PSIA and full scale output (typically 5 VDC) at full scale pressure (in PSIA).  PSIA (pounds per square inch absolute) is a unit of pressure measured relative to a full vacuum.  A vacuum can refer to any pressure between 0 PSIA and 14.7 PSIA.