Calculate $R_{+}$for Figure $6-23.$

Determine $R_Y$ for Figure $6-24.$

Determine the current through each resistor in the parallel circuit of Figure $626$

FIGURE $6-26$

Find the voltage Is across the parallel cinuit in I igure $6-27$

HIGRL $6-27$

How much voltage is required to produce $20mA$ of current through the circuit of Figure $6-28?$

FICURE $6-78$