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For those of you who need to send in a guitar signal but don't always want to be strumming the shop guitar when you need to be looking at the scope.
I posted a circuit at my web site (Geofex) for a test oscillator I call the Fake Guitar Oscillator. It's a simple fixed frequency tone generator which can be switched to generate a repetitive series of decaying ring signals, much like plucking a single string and letting it fade away. The link is on the intro page.
It is a Twin T oscillator, which can be set for either continuous operation or a variable fade-out time. It includes a "plucker" which will disturb the Twin T resonator every so often and trigger a ring. The interval between plucks is variable between about 10 times per second and once every two seconds. Notes can be set for banjo-like fade out all the way up to continuous oscillation.
There is a switch to set it to just send out a sine wave all the time. Frequency is fixed by the components, but you bench hackers could change that. Right now it's somewhat under 1kHz. The switch selects plucked or continuous sine out.
Output level is a max of about +/-600mV peak, with a volume control to run that down to zero.
Notice that you *will not* like the sound of this thing hitting the same tone and decaying over and over any more than you like a sine wave droning through speakers.
I posted a circuit at my web site (Geofex) for a test oscillator I call the Fake Guitar Oscillator. It's a simple fixed frequency tone generator which can be switched to generate a repetitive series of decaying ring signals, much like plucking a single string and letting it fade away. The link is on the intro page.
It is a Twin T oscillator, which can be set for either continuous operation or a variable fade-out time. It includes a "plucker" which will disturb the Twin T resonator every so often and trigger a ring. The interval between plucks is variable between about 10 times per second and once every two seconds. Notes can be set for banjo-like fade out all the way up to continuous oscillation.
There is a switch to set it to just send out a sine wave all the time. Frequency is fixed by the components, but you bench hackers could change that. Right now it's somewhat under 1kHz. The switch selects plucked or continuous sine out.
Output level is a max of about +/-600mV peak, with a volume control to run that down to zero.
Notice that you *will not* like the sound of this thing hitting the same tone and decaying over and over any more than you like a sine wave droning through speakers.
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