Hello guys, I'm currently working on a simple audio switch circuit and I can't quite figure it all out..
The problem is as follows: there is a walkie-talkie, an iPod and headphones. If there's no signal from the radio, iPod is routed to headphones by default; if there is any signal from the radio - the iPod signal is muted or dimmed and you hear the audio from the radio. The signal from the radio comes pretty loud, looks like it's amplified.
There are a couple of problems - first, I have to admit that my knowledge in circuits is pretty far from advanced, I'm trying to learn though. Another problem is that there is no Radioshack in Canada - so all that's available to me atm is a bunch of npn/pnp transistors, 4000 series diodes, maybe a relay, and maybe a 741 opamp. And finally, I need this little gadget for the trip and I have one week at most to build it..
That's what I came up with:
However, I'm TOTALLY lost trying to place the capacitors and resistors properly.. any advice?
The diode bridge rectifies the signal, then there is a battery because the audio signal itself doesn't seem to be able to trigger the first transistor (am I wrong?). The first transistor is a not-gate, so it requires a battery (which is a little bit weird - cause this circuit will consume power whenever NOT used..). This not-gate doesn't work as I want it to though - when there is input signal, the output is not zero, it's like (1.5V - epsilon). Should I base the circuit on transistors in the first place? Does it really need two AA's? If it does, how long would the batteries last? Wouldn't the second transistor hurt the iPod sound?
This circuit kinda-works, whenever a sound signal comes from the radio, the iPod signal is dimmed a little bit and you can hear the radio. However, there are some distortions with the radio signal and also it's very loud (currently, this circuit works only if the radio is set to it's max volume).
I hope this doesn't look like another "dude" post, I'm really trying to figure things out but having no experience in circuits whatsoever it's getting really hard.
The problem is as follows: there is a walkie-talkie, an iPod and headphones. If there's no signal from the radio, iPod is routed to headphones by default; if there is any signal from the radio - the iPod signal is muted or dimmed and you hear the audio from the radio. The signal from the radio comes pretty loud, looks like it's amplified.
There are a couple of problems - first, I have to admit that my knowledge in circuits is pretty far from advanced, I'm trying to learn though. Another problem is that there is no Radioshack in Canada - so all that's available to me atm is a bunch of npn/pnp transistors, 4000 series diodes, maybe a relay, and maybe a 741 opamp. And finally, I need this little gadget for the trip and I have one week at most to build it..
That's what I came up with:
However, I'm TOTALLY lost trying to place the capacitors and resistors properly.. any advice?
The diode bridge rectifies the signal, then there is a battery because the audio signal itself doesn't seem to be able to trigger the first transistor (am I wrong?). The first transistor is a not-gate, so it requires a battery (which is a little bit weird - cause this circuit will consume power whenever NOT used..). This not-gate doesn't work as I want it to though - when there is input signal, the output is not zero, it's like (1.5V - epsilon). Should I base the circuit on transistors in the first place? Does it really need two AA's? If it does, how long would the batteries last? Wouldn't the second transistor hurt the iPod sound?
This circuit kinda-works, whenever a sound signal comes from the radio, the iPod signal is dimmed a little bit and you can hear the radio. However, there are some distortions with the radio signal and also it's very loud (currently, this circuit works only if the radio is set to it's max volume).
I hope this doesn't look like another "dude" post, I'm really trying to figure things out but having no experience in circuits whatsoever it's getting really hard.
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