Hartley Oscillator Design

[DaveE]

How can 35mA flow through he 4.7k emitter resistor with a supply of 9 volts?

It can't. It can, however, flow through C2 which has an impedance magnitude of 160ohms at 2.1MHz. I suspect it's more complex than just C2 though since the node is coupled into the tank. You have to look at all of the possible paths.

 

[Baluncore]

I tend to think that even with corect bias, the device will tend to

Tend to what?

In reality it will not start without C3 to isolate the DC base bias from the broadband short of the tank circuit. Without C3, the base bias resistors are irrelevant.

Oscillation of the tank could be started by momentarily connecting the base (and tank) to the +9V supply.

In a Spice model that can be done by using the 'Dot Initial Condition' command to set the initial inductor current to 25 mA by;
.IC I(L) = 25m

Operation without C3 is moot anyhow. No one would build such a circuit. They might however fail to include the capacitor symbol in a schematic diagram. We don't have the original reference, so there is no telling how it happened.