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Hello, I'm new to this topic as it is my school works, I try to simulate the diagram below by using Proteus which I follow accordingly with the labsheet given from my school.

The problem is the parameters for the Carrier Wave & Audio Signal is unknown while VCC=15V. There's no output when I run the simulation. Can someone suggest me to solve this problem?

The parameters for R & C were already given in the labsheet which I just follow it and should not be changed.

Updates : I try to run the same circuit by using Multisim and it does generates waveform. But now the question is, what parameters should I change to get the best AM modulation ?

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  • 6
    \$\begingroup\$ All the inputs to the 'scope are connected to Ground - is that what you want? \$\endgroup\$ Commented Mar 25, 2021 at 3:18
  • \$\begingroup\$ Your "scope" is not measuring the output. \$\endgroup\$ Commented Mar 25, 2021 at 3:36
  • \$\begingroup\$ I've change the ground and it solved the problem ! But how to find the best parameters for this AM output waveform ? \$\endgroup\$
    – Azim
    Commented Mar 25, 2021 at 4:38
  • \$\begingroup\$ If you've changed the wiring, please post a revised schematic so we know how your actualcircuit is connected. \$\endgroup\$ Commented Mar 25, 2021 at 5:04
  • \$\begingroup\$ imgur.com/3Cu0KOy \$\endgroup\$
    – Azim
    Commented Mar 25, 2021 at 5:14

1 Answer 1


There are a couple of schematic glitches:

  1. Scope signals (obvious)
  2. The load R must be >= Rc in for large swing to not starve the collector signal of current when AC coupled.

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