Hi i have a radio circuit, but i wish to incorperate the volume control circuit on this site into the circuit. Which part of the circuit do i fit it into and how do i connect it. My circuit is:http://www.rapidonline.com/netalogue/specs/70-0110e.pdf
It is the worst cheap AM radio circuit that I have ever seen. It is missing everything that real radio circuits have including a volume control.
It is so simple that it cannot separate stations and it is easily overloaded by local stations. Its output volume changes by the strength of the station it receives which is ridiculous.
I do realise that, it is only a school project, so calm down. Thanks for answering my question in the least helpful way possible, i really appreciate it
Hey it's okay. You got a reply from the audioguru. We are audiophiles so when we are presented with crappy designs or poor sound quality we tend state it quite clearly. Like I always say it isn't any good for us to tell you "what to do". The whole aim of your teachings is for you to figure out "what to do". You've got teachers right? Ask them. Implementing some form of volume control in a low power circuit is remarkably simple and yet I shouldn't just tell you what to do because you want to learn right?
Resistors... Study them, then learn about variable resistors. In a low power circuit a small variable resistor will often be sufficient. Now you go ahead and try to figure out where to put it. However like audioguru said there isn't any form of AGC (Automatic Gain Control) in this circuit.
When one person suffers from a delusion it is called insanity. When many people suffer from a delusion it is called religion.
I was wrong. The MK484 TRF AM radio IC is the improved new one, not the obsolete old ZN414. It does have AGC but is still missing many parts that are in a real AM radio. Look at MK484 in Google and see that some people put a 10k volume control to replace R2. Then the volume reduces as the battery runs down.
The ZN414 was made by Ferranti and was a very good chip. It is obsolete only because Ferranti stopped making it - not because it was a poor design. Its parameters are identical to the MK484 according to the Ferranti data booklet I have for it.
Both chips have the same AGC range (>30dB). I used a ZN414 for the IF stage of a radio control radio monitor and used a meter in the chip's supply current (AGC controlled) as an 'S' meter. The scale was marked linearly in 3dB steps. The receiver was an excellent performer and could easily separate adjacent transmissions with adverse signal strengths 25kHz apart.
The tuned coil determines selectivity and the following is a quote from the Ferranti booklet. "...In practice, it is easy to obtain a 'Q' of over 150 at 1MHz (this corresponds to a bandwidth of 7kHz)".
I need three active devices, so i'm thinking use a darlington pair as two of them and then the MK484 as the other if it is advised not to use the digital volume control on this site. Originally i was going to use the Digital volume circuit along with the MK484 and the amplifier as my three devices which is why i did not want to use a simple potentiometer.
jagoodjee if it was me I would use a digital volume control if I had the time to wait for the delivery before the project was due in. If there isn't enough time I would just use a potentiometer. It's up to you.
However if I were to be given this project and I was able to make large modifications to it I would jazz it up so much it would probably no longer resemble the original. It would have a voltage regulated power supply for starters. It's no good having performance wonder all over the place with battery voltage.
When one person suffers from a delusion it is called insanity. When many people suffer from a delusion it is called religion.
Volume control how to implement in radio circuit
Posted - Feb 23 2010 : 12:05:26 PM
