1) The horrible circuit has its first opamp as an inverter that has a low input impedance of 5.1k ohms. Therefore it causes the selectivity to be low because the tuned circuit is a heavily loaded. If the opamp has a non-inverting input then its input impedance would be very high and the selectivity would be much better.
2) The circuit has only a single tuned circuit so its selectivity will be pretty bad when compared to a normal radio that has many tuned circuits.
3) The very old opamp used as the RF amplifier has a poor high frequency response. Its max gain at 1.6MHz (the top of the AM broadcast band) is only 3.
Its max output level at 1.6MHz is only 2V p-p.
4) The detector diode should be inside the negative feedback loop of a good RF opamp for good sensitivity.
5) The circuit is missing automatic-gain-control like all normal AM radios have so that weak and strong stations have the same volume level.
6) The circuit is missing a power amplifier to drive a speaker.
I wonder why the circuit needs two 18V batteries??
I found this circuit on internet (one random page). I need (for college) to design and explain one simple AM demodulator + amplifier. (how does it works...).
Can you give me one simple circuit like that (which works )
I found this circuit on internet (one random page). I need (for college) to design and explain one simple AM demodulator + amplifier. (how does it works...).
Can you give me one simple circuit like that (which works )
I found this circuit on internet (one random page). I need (for college) to design and explain one simple AM demodulator + amplifier. (how does it works...).
I found this circuit on internet (one random page). I need (for college) to design and explain one simple AM demodulator + amplifier. (how does it works...).
Can you give me one simple circuit like that (which works )