- #1
wwoollyyhheeaa
- 15
- 0
If an amplifier (audio or RF) has the collector of a transistor for its output electrode and assuming the transistor operates in its active region (not saturated or cut off) the output impedance of the amplifier will be high (several 10s of kilohms). If now a tuned circuit is connected as a load to the amplifier's output and impedance-matched to a real load R (the input impedance of the following amplifier) the apparent load on the collector of the transistor is n sqared x R (n is the turns ratio of the matching transformer). But when the amplifier is working it delivers ALL its output power to R. The apparent load doesn't dissipate any power. Why not? It is resistive (wholly real) and it has current flowing in it.