| 摘要 |
<p>PURPOSE:To reduce the current consumption of a switching element by using a semiconductor switching element for a switching element to turn on/off a speaker and turning on/off the speaker with a control bias. CONSTITUTION:When a speaker 15 built in a cassette tape recorder is to use as an alarm speaker informing the end of the tape at recording, a switch 19 is closed. As the result, bias current flows into a pair of transistors 16a and 16b connected in reverse parallel through driving resistors 17 and 18 and a semiconductor switching element 16 is connected, turning on the speaker 15. To check the generation of alarm sound, the switch 19 is closed, so that the semiconductor switching element 16 is disconnected and the speaker 15 is turned off.</p> |
