Making electronic attenuators with discrete components

Photocoupler

The attenuator is a circuit that introduces a predetermined attenuation over a specified frequency range. It is generally indicated by the number of decibels of the introduced attenuation and the ohmic number of the characteristic attenuator resistance. Attenuators are widely used in cable television systems to meet the multi-port pair level requirements. Such as the input of the amplifier, the control of the output level, and the control of the branch attenuation. The attenuator has two types of passive attenuators and active attenuators. The active attenuator cooperates with other thermal elements to form a variable attenuator, which is used in the amplifier for automatic gain or slope control circuits. Passive attenuators have fixed attenuators and adjustable attenuators.
Two low voltage, low power Zener diodes are used to control the level of the audio signal of the electron. The attenuation range is 6 to 58 dB for an input current of 0.042 mA from 0.042 corresponding to a control voltage from 2.7 to 7.5V. If the control voltage is limited to 5V, the attenuation is approximately 2dB at 30dB.