The circuit shown in Figure P9.25 is a 9-V battery charger. The purpose of the Zener diode is to…

The circuit shown in Figure P9.25 is a 9-V battery charger. The purpose of the Zener diode is to provide a constant voltage across resistor R
2
, such that the transistor will source a constant emitter (and therefore collector) current. Select the values of R
2
, R
1
, and VCC such that the battery will be charged with a constant 40-mA current.