An attenuator is an electrical device that lowers the level of an electric signal without appreciably distorting its waveform. These devices are often used in electronics circuits to ensure an appropriate, safe voltage. They are widely used in cell phones, cordless phones and capacitors which provide an adjustable resistance by varying their capacity for storing an electric charge. However, they can also be found in sound systems and other applications where it’s necessary to reduce power levels or prevent damage. Let’s take a closer look at how each type works!
Types of the Attenuators and Their Uses
An attenuator is a two-port resistive network that reduces or “attenuates” the power flowing from a source to a connected load to a level that is acceptable.
Attenuators can also be used to protect the measuring device from signals that would damage it while taking measurements within electric circuits.
A simple passive attenuator reduces the quantity of energy supplied to a connected load by a single fixed amount, or a variable percentage, or in a series of pre-programmed switchable steps.
Fixed value attenuator’s attenuation value cannot be varied. Fixed attenuators are used to reduce the power transmission in an electronic circuit. These types of resistors have a single set resistance value and can be easily adjusted by sliding an outer case along the resistor body. What does it do? Fixed type fattenuator is mainly designed for situations where better control over adjustment would be desirable than achieved with simple wire links. Fixed attenuation values range from 1dB to 30dB.
Continuously Variable Attenuators
Unlike fixed attenuators, continuously variable attenuators can be adjusted manually within a defined range and resolution to achieve the required reduction. Variable attenuators are used as an adjustable voltage divider or an impedance matching device which allows to choose any desired level of output ranging from maximum through no attenuation at all down to very low values close to zero ohms. In average, variable attenuation levels ranging from 1 dB to 30 dB.
One of the most important characteristics is an adjustable attenuator’s ability to change its power rating during use. The resistive element in an automatic step attenuator does not have an integral switch which would allow adjusting it while the circuit is powered up. Instead, an external control changes a separate potentiometer or resistor connected between two taps on an inductor coil within the unit, causing sufficient resistance to make contact with other tap(s) and reduce output voltage level by an exact amount.
Step type fattenuators are widely used for matching impedances when connecting together different circuits having different source impedance levels (e.g., 50 ohms). It also allows for achieving any desired degree of load termination without resorting to additional equipment. Manual step attenuator usually provides attenuation range from 0 to 90dB.
DC Blocking Attenuators
DC blocking attenuators are used for an electronic signal to be transmitted from a high level to a low level without the DC component of the input signal being passed on. They allow an AC waveform such as an audio or video sine wave, which has both positive and negative voltage peaks but no DC value, through while stopping any unwanted DC voltages present within an input signal. These types of resistors have either one end left open-circuit (commonly called ‘unterminated’) or with its two ends shorted together (a single connection).
What does it do? Due to their unique function, they can also be found in semi-professional microphone and other equipment where the signal level is rather low. In this case, using a conventional high value resistor would severely load down the microphone’s output. Thus, it’s affecting a sound quality or introducing noise into an external circuit from an internal preamplifier stage with no direct path for current flow through the latter. Because the line level signals are typically in range of 0.5..2V and the microphone signals are in millivolt range, quite much attenuation is needed to match the signal levels. This means that typically you will need 40-50 dB of attenuation.
Attenuators Do Really Work!!!
You may be wondering how this applies to you and your life. Well, I’m glad you asked! Attenuators are often used in electronics circuits as a safety precaution so that an excess voltage does not damage the circuit or cause it to malfunction. This can also help protect people from dangerous electrical shocks. As you’ve seen in the examples above, the attenuators have many practical applications for both electronic and human use alike. If you want more information on these devices or need help with any related questions please feel free to contact us anytime – we would love to hear from you!