Pasif Zayıflatıcılar / Passive Attenuators

Debilitators are a two-input resistant network designed to weaken the power provided by the source to a level suitable for connected load. Passive debilitator reduces the amount of power given to the connected load by either a single fixed amount, or a variable amount, or a series of known interchangeable steps. Debilitators are often used in radio, satellite, communication and transmission line applications to weaken a stronger signal. Passive Debilitator is a completely passive resistant network (hence no supply) used in a wide range of electronic equipment to expand the range of dynamic measuring equipment by adjusting signal levels to allow oscillators or amplifiers to match impedance to reduce the effects of signals. It is used to provide insulation between different circuit stages depending on improper input/output terminations or applications as shown simply.

Debilitating Link

Simple debilitating networks (also known as "pads") can be designed to produce a constant degree of "slimming" or to give a variable amount of weight loss in predetermined steps. Standard fixed attenuating networks, commonly known as "debilitating pads", are available in certain values from 0 dB to 100 dB. Variable and switched debilitators are basically adjustable resistance networks that show a calibrated increase in weight loss for each keyed step, for example steps of -2dB or -6dB per key position. Then a Debilitating is a four-terminal (two-port) passive-resistant network designed to produce "unbreakable" weakening of the output electrical signal at all frequencies without phase shift (active types using transistors and integrated circuits are also available). Unlike a passive type RC filter network, and therefore to achieve this, debilitators should not be made of pure non-inductive and wire-winded resistors, as reactive elements will give frequency discrimination.

Simple Passive Attenuator

Debilitators are the opposite of amplifiers, as they reduce gain with a resistant voltage dividing circuit, which is a typical debilitating one. The amount of weight loss in a given network is determined by the following ratio: Output/Input. For example, if the voltage of a commissioning is 1 volt (1V) and the output voltage is 1 milli-volt (1mV), the amount of weakening is 1mV/1V, which is equal to 0.001 or 1000th reduction. However, the use of voltage, current and even power ratios to determine or express the amount of weakening that a resistant debilitating network called the slimming factor can have can be confusing, so the degree of weakening for passive attenuator is normally expressed using a logarithmic. The scale given in decibels (dB) makes it easy to deal with small numbers such as 0.001.

Weight Loss Ratings

The performance of a debilitator is expressed by the number of decibels per octave to the frequency of the input signal. Decibels abbreviated as "dB" are usually defined as the logarithm or "log" measure of the voltage, current or power ratio and represent a tenth of a Waist (B) of 1/10. In other words, it takes 10 decibels to make a Waist. Then, by definition, the ratio between an input signal (Vin) and an output signal (Vout) is given in decibels as follows: Note that decibels (dB) are a logarithmic ratio and therefore do not have a unit. That is, the value of -140dB represents a weakening of 1:10,000,000 units or a ratio of 1 ratio to 10 million. In passive debilitating circuits, it is usually convenient to assign the input value as a reference point of 0 dB. This means that regardless of the actual value of the input signal or voltage, the weakening is used as a reference to compare the output values and is therefore assigned to a value of 0 dB. This means that any output signal voltage value below the reference point will be expressed as a negative dB value ( -dB ). For example, a weakening of -6dB indicates that the value is less than 6 dB below the 0 dB input reference. Similarly, if the output/input ratio is less than one, for example, 0.707, this corresponds to 20 log(0.707) = -3dB. If the output/input ratio = is 0.5, this corresponds to 20 log(0.5) = -6 dB, and this continues and standard electricity attenuation tables are available to save time of calculation.

Passive Debilitating Calculation Example

A passive debilitating circuit has an insertion loss of -32dB and an output voltage of 50mV. What will be the value of the input voltage? The antelog of -1.6 (log-1) is given as follows: If the output voltage is produced with a weakening of 32 decibels, an input voltage of 2.0 volts is required.

Standard Slimming Table

Log Value20log (1)20log (0.7071)20log (0.5)20log (0.25)20log (0.125)20log (0.0625)20log (0.03125)20log (0.01563)20log (0.00781)
in dB0-3dB-6dB-12dB-18dB-24dB-30dB-36dB-42dB

This reduction in voltage, current or power expressed in decibels by adding the debilitating circuit to an electrical circuit is known as insertion loss, and the minimum loss matches the debilitating designs with the minimum loss of the unequal impedance circuits in the matching network. Now that we know what a passive debilitator is, now that we know how a signal can be used to reduce or "weaken" the power or voltage level, it does not provide little or no loss of distortion and addition in an amount expressed in decibels.

Passive Attenuating Design

Voltage Divider Circuit There are many ways in which resistors can be regulated in debilitating circuits, which is the simplest type of passive debilitating circuit. The potential voltage divider circuit is often known as the "L-pad" debilitator because the circuit diagram resembles an inverted "L". However, there are other common types of debilitating networks, such as "T-pad" debilitating and "Pi-pad" (π) debilitating, depending on how you connect resistant components together. These three common types of debilitating are shown below. The above debilitating circuit designs can be arranged in a "balanced" or "unbalanced" manner, with the movement of both types the same. The balanced version of the "T-pad" debilitator is called the "H-pad" debilitator, and the balanced version of the "π-pad" debilitator is called the "O-pad" debilitator. There are also bridged T-type debilitators. In an unstable attenuator, resistant elements are connected to only one side of the transmission line, while the other side is grounded to prevent leakage at higher frequencies. In general, the grounded side of the debilitating network does not have resistant elements and is therefore called "common line/common". In a balanced debilitating configuration, the same number of resistant elements are evenly connected to both sides of the transmission line with the soil located at a center point formed by balanced parallel resistors. In general, balanced and unbalanced debilitating networks cannot be connected, since this causes half of the balanced network to short-circuit the soil through unbalanced configuration.

Key Debilitators

Instead of having a single debilitating to achieve the required degree of weight loss, separate attenuating pads can be connected or gradualized to increase the amount of weight loss in certain slimming steps. Multipolar rotary switches, push switches, or adjusted push button switches can also be used to connect or bypass fixed attenuating networks in any desired order from 1dB to 100dB or more, making it easy to design and create switching debilitating networks.By activating the appropriate debilitators, the slimming can be increased or reduced in fixed steps, as shown below. Here are four independent resistant debilitating networks cascading together in a network of serial ladders, where each debilitator has a value of twice that of the previous one (1-2-4-8). Each debilitating network can be translated into "inside" or "out" of the signal path as required by the corresponding switch, which produces a step adjustment debilitating circuit that can be changed from 0dB to -15dB in 1dB steps. Therefore, the total amount of weakening provided by the circuit will be the sum of the four debilitating networks with "IN" switches. Therefore, for example, a weakening of -5dB requires the SW1 and SW3 switches to be connected, and a weakening of -12dB requires the SW3 and SW4 switches to be connected.


  • A debilitator is a four-terminal device that reduces the amplitude or strength of a signal without disrupting the signal waveform, a debilitating can generate a certain amount of loss.
  • The debilitating network is placed between a source and a load circuit to reduce the size of the source signal by a known amount suitable for load.
  • Attenuators can be constant, completely variable, or variable in known slimming steps such as -0.5dB, -1dB, -10dB, etc.
  • It can be in a debilitating, symmetrical or asymmetrical form and balanced or unstable.
  • Constant attenuators, also known as "pads", are used to "match" unequal impedances.
  • A debilitator is the opposite of an amplifier.
  • Debilitators are passive devices that are usually made from simple voltage dividing networks. Switching between different resistors, adjustable gradual debilitators and debilitating ones that can be adjusted continuously using a potentiometer can be used.

A constant value of "K" can be used to simplify the design of the debilitator. This "K" value is the ratio of voltage, current or power corresponding to a specific dB weakening value and is given as follows: We can produce a set of constant values called "K" values for the different amounts of weakening given in the table below.

K constant1.05931.12201.25891.41251.58491.77831.99533.162310.000

Fixed value attenuators, called "attenuation pads", are mainly used to reduce voltage, dissipate power or improve impedance compatibility between various incompatible circuits in radio frequency (Rf) transmission lines. Line level debilitators in the front amplifier or audio power amplifiers can be as simple as a 0.5 watt potentiometer or voltage divider L-pad designed to reduce the amplitude of an audio signal before it reaches the speaker and reduce the volume of the output. In measurement signals, high-power debilitating pads are used to reduce the amplitude of the signal by a known amount or to protect the measuring device from high signal levels that may otherwise cause harm. In the next lesson on debilitators, we will look at the most basic type of resistant debilitating mesh, commonly called "L-type" or "L-pad" debilitating, which can be done using only two resistant components. The "L-pad" debilitating circuit can also be used as a voltage or potentially divisive circuit.