Stevie_j_b
New Member
Hi all,
I'm posting here in the hope that someone can help me, and hopefully I can elaborate the subject out for you sufficiently!
I work for a design and development company, and we deal with a wide variety of work, including recreations of training aids. Something has come into the office which we are to reverse-engineer, in a bid to reproduce (and simplify) for repeated production. Basically, this device functions as a training aid. The device contains a digital countdown timer (AA battery powered), which counts down from a set value. Upon reaching zero, the timer buzzer goes off. The intermittent buzzing isn't sufficiently loud, and needs to be constant not intermittent, and therefore the leads connecting to the speaker are spliced off into a little circuit, which activates a constant wail from a larger speaker, connected to a 9v battery.
I did a bit of searching on Google for component descriptions, and we have a thyristor, transistor, diode, and various resisters. Since I'd never covered thyristors in my Mech Eng degree course, I dug around a little, and it seems this is used to latch upon an input from the little speaker, forcing the loudspeaker to wail permanently. I had a feeling the transistor is used to drive up the output from the little speaker to above the threshold (1.5v) on the thyristor gate, so I had a play, but while the larger speaker does beep, it does so intermittently, in sync with the smaller speaker.
I'm sure this is quite a simple circuit I need, but my basic level of knowledge has forced me into a dead end! Is there anyone who understands what I need, and has any direction for me? I can try and give you more information if it's required, so let me know!
Thanks in anticipation,
Steve
I'm posting here in the hope that someone can help me, and hopefully I can elaborate the subject out for you sufficiently!
I work for a design and development company, and we deal with a wide variety of work, including recreations of training aids. Something has come into the office which we are to reverse-engineer, in a bid to reproduce (and simplify) for repeated production. Basically, this device functions as a training aid. The device contains a digital countdown timer (AA battery powered), which counts down from a set value. Upon reaching zero, the timer buzzer goes off. The intermittent buzzing isn't sufficiently loud, and needs to be constant not intermittent, and therefore the leads connecting to the speaker are spliced off into a little circuit, which activates a constant wail from a larger speaker, connected to a 9v battery.
I did a bit of searching on Google for component descriptions, and we have a thyristor, transistor, diode, and various resisters. Since I'd never covered thyristors in my Mech Eng degree course, I dug around a little, and it seems this is used to latch upon an input from the little speaker, forcing the loudspeaker to wail permanently. I had a feeling the transistor is used to drive up the output from the little speaker to above the threshold (1.5v) on the thyristor gate, so I had a play, but while the larger speaker does beep, it does so intermittently, in sync with the smaller speaker.
I'm sure this is quite a simple circuit I need, but my basic level of knowledge has forced me into a dead end! Is there anyone who understands what I need, and has any direction for me? I can try and give you more information if it's required, so let me know!
Thanks in anticipation,
Steve