John, Opposite effect. 2 resistors in series reduces current flow. These are the same 16ohm resistors used in the PS-2 engines. The PS-1 has them wired in series so each drops half the voltage of the track.
The PS-2 are in parallel and effectively 8 ohms, so the current draw is not the issue.
When the transistor conducts at high track voltage and shorts one resistor, the other then gets full voltage and increased current with an effective 16 ohm load. Just an interesting way to approach solving a problem. G
Actually, it works the way I thought it should. At low voltages, Q1 will be off, so Q2 will be conducting, shorting out the one resistor. When you pass the threshold of the zener and the base-emitter junction drop, Q1 will turn on, removing the base-emitter bias of the Q2, turning it off.
It makes no sense to have it work the other way.
John, You are correct on how the transistors worked, I was viewing it from the load side and how cutting in an additional 16 ohm resistor in series was effecting the current. I
From 6 to 13V the single 16 ohm resistor would draw .375 to .8125A and produce 10.56 Watts of heat. When Q2 goes off and the 2 resistors are in series at the transition point of 13V the current would drop to .406A and 5.28W output. Max W would be 10 at 18V. So the output would seem to dip at 14V and then flatten back out at 16-18 V.
This never gets over about .56 amps of draw.
If you kicked out a resistor at 13V, so the unit was on a single 16ohm resistor, you would get a jump of 5Watts at transistion, and Max out at 1.125A and a 20W at 18V! More linear response.
So it does seem like two elements produce more smoke than one even though the current is reduced in half. G
