🔍 Key Concepts

• Transistor polarity and configuration in a series regulated power supply • Rectifier diode orientation in relation to transformer secondary and ground • The role of base bias resistor (R1) in controlling transistor base current

💭 Think About

• Look at how D1 and D2 are connected to the transformer secondary and the circuit ground. Would reversing them still allow rectified DC to appear where it is needed? • Consider the type of transistor symbol shown for TR1. In a typical series pass regulator with the emitter feeding the output, which polarity (NPN or PNP) is usually used with a positive output supply? • Think about what would happen to the transistor if R1 were much too low. Would the circuit fail instantly, or would some other protective or limiting factor in the regulator prevent immediate destruction?

✅ Before You Answer

• Verify the arrow direction on TR1 (NPN vs PNP) and how its collector, base, and emitter are connected in the regulator path. • Check the diode polarity marks (anode/cathode) against the intended direction of current flow from the transformer secondary to the filter and regulator. • Confirm whether any current-limiting components or reference/feedback elements exist that would limit base current through R1.