The component values in the circuit below were found using the excel quick start calculator.
Profiling the circuit on the bench yields the following Vout vs. Vin
| Vin | Vout |
| 12.01 | 9.00 |
| 13.00 | 9.00 |
| 14.02 | 9.00 |
| 15.01 | 9.00 |
| 16.02 | 8.99 |
| 17.00 | 8.98 |
| 18.01 | 8.98 |
| 19.01 | 8.96 |
| 20.00 | ~8.0-8.95 |
| 21.01 | ~7.5-8.98 |
| 22.00 | 7.28 |
| 22.50 | 6.27 |
| 23.01 | 5.21 |
| 24.00 | 4.86 |
| 25.00 | 4.28 |
| 26.01 | 3.94 |
| 27.00 | 3.63 |
| 28.00 | 3.49 |
The circuit is feeding a speaker amp, so the current draw will necessarily fluctuate. But, it is nominally in the neighborhood of 60 mA.
Right around 20Vin the circuit seems to lose the ability to keep the output at a steady 9V. The output bounces around as the audio is played. This continues to 21Vin. By 22 Vin the output is low enough the speaker amp no longer functions. The output continues to drop as the input increases from there.
Thanks in advance!
