0
The radio signal at the aerial is a few micro volts. At the loudspeaker the signal will be a few volts or tens of volts. So we have to have a lot of amplification between the aerial and the output. Once the signal has been tuned in, it is quite convenient to then perform most of the amplification needed at one radio frequency - typically a little below 500 kHz. So after the tuning processes, you will have a couple of stages of IF, followed by an audio detector, and some audio amplification. [Intermediate Frequency - a frequency between that of the radio station, and the audio waves we really want.]
However, the signal from the station is not perfectly steady - it fades in and out in level - particularly if the station is distant, or if the travel path is changing. The AGC [Automatic Gain Control] is designed to even out these variations in signal strength. It does this by rectifying part of the signal to DC, after the IF stages, and feeding this DC back as a bias to lower the amplification of the IF stages.
Since it can only lower the amplification of the IF stages, it follows that the IF's must have more gain available than needed, so as to enable the AGC to have something to act on. This is why they must have so much gain available in the first place.
What else can I help you with?
What is delayed agc?
In a normal AGC, even the unwanted signals gets amplified, But u dont want that to happen, so until the Input Signal strength reaches a threshold, the AGC feedback signal is not applied to the amplifier biasing circuit..
What is vector impedance meter explain with circuit diagram?
A vector impedance meter is used to measure impedance and phase angle, this is done by calculating voltage and current through an impedance and then calculating Z and phase angle with that, now there are two modes for operation i.e constant current mode and constant voltage mode. CONSTANT CURRENT MODE construction = first of all there is a wien bridge oscillator(w) to choose frequency then an AGC amplifier(a) to regulate current then a z switch control(zs) which regulates gain of AGC amplifer, feedback to AGC amplifier is done by an dc differential amplifier(dc) dc | | | w--------->a--------->z now there is an ac differential amplifier too(ac) which gets one input from the z switch and one from the unknown impedance(imp), and there is a transconductance amplifier too which gets one of his input from the unknown impedance dc<------------------------------------------- | | | | | | w--------->a--------->z----------->ac-------------|------------> z meter | | | | | | _____| | | | | | | | | | | | imp | | | | | |________|___>rt___>| working---> in constant current mode we have to maintain constant current through impedance so current is made to come to unknown impedance from z switch, then that current goes through trans-resistance amplifier, which converts that current to a voltage that is sent to a dc differential amplifier and is compared with a reference voltage in dc differential amplifier then the difference between voltages is amplified and sent to AGC amplifier, so AGC together with z switch this way maintains constant current through unknown impedance, now for calculation z-magnitude, ac differential amplifier gets input from unknown impedance and z switch, so difference is amplified and sent to a band pass filter which filters out then the filtered signal is sent to a z-magnitude meter which is calibrated to read z directly.
Does 5 AGC mean 5 amp?
No, "5 AGC" typically refers to a type of fuse, specifically a 5-amp AGC fuse. The "AGC" designation indicates a specific style and rating of the fuse, which is designed to protect electrical circuits by breaking the circuit if the current exceeds 5 amps. So, while "5 AGC" does imply a 5-amp rating, it specifically denotes a fuse rather than just the current itself.
Can a 10 amp AGC fuse be used in a 10 amp rated DC circuit?
Yes, a 10 amp AGC fuse can be used in a 10 amp rated DC circuit as long as the fuse rating matches the circuit's ampacity. This ensures that the fuse will blow before the circuit is overloaded, protecting the circuit from damage and potential hazards.
How is automatic gain control bias voltage developed in a valve superhet radio reciver circuit?
The signal is changed to dc in the AGC circuit to change the gain. A weak signal will increase gain.
Why do you use a delayed AGC?
The disadvantage of automatic gain control, attenuating even the weak signal, is overcome by the use of delayed automatic gain control (dagc).
Difference between ABC and agc fuses?
ABC = Ceramic Body AGC = Glass Body
What does AGC stand for on a fuse?
AGC is a fuse type IE; the glass ones with the metal tips on the ends.
What does ACG mean on a fuse?
Are you sure you do not mean AGC? AGC stands for Automotive Glass Cartridge (Fuse). AGC fuses are fast acting fuses that will blown very quickly to protect components.
Types of Automatic gain control circuits?
2 types 1.simple AGC 2.delayed AGC
What is the difference between AGC and ABC fuses?
AGC fuses have glass body. ABC fuses have a ceramic body.
Is it harmful to use a 3 AGC fuse where an AGC 1 was used but it keeps breaking?
Possibly. If a fuse keeps blowing it you should check the circuit and the loading. Using a higher rated fuse may result in the appliances being damaged because of power overload. Worse, it could result i a short or a fire. DON'T RISK IT!
