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Hy martino,I'd like to build an oscillator able to work with 12 or 24V power supply.
The output is a square wave of variable amplitude up to nearby the power supply voltage in the range of 100 to 2000Hz (precision is not an issue).
The load capability should be at least 100mA.
Regards,
Thank You Spec, but I don't understand what of the proposed solutions, can work with a power supply of 12 - 24V.
I have just re read your opening question and realise that I may have misunderstood the requirement.
How would it be if the circuit operated from a fixed 24V supply and the output square wave could be continuously adjusted by a potentiometer from 0V peak to peak to 24V peak to peak?
The frequency would also be adjustable by a potentiometer as previously mentioned.
spec
I gather you do not have a signal generator which can supply the 3 to 10mA per LED opto load in the target PLC,with suitable current limiting R.I'd like to build an oscillator able to work with 12 or 24V power supply.
The output is a square wave of variable amplitude up to nearby the power supply voltage in the range of 100 to 2000Hz (precision is not an issue).
The load capability should be at least 100mA.
Regards,
How variable? If it never has to go below 1.5 V, then this reduces to a low-dropout regulator making a variable voltage level and an oscillator with a PNP switch on the output.A variable output from 0V to supply voltage should be much appreciated and useful to evaluate the input sensitivity of the PLC.
Because it doesn't have one?Hey guys: Idea. Why not drive the shutdown pin of an LM317?
A 1.25 V Vmin doesn't sound like "shut down" to me. I thought about using a 317 for the variable output level part, but the 3 V overhead is too great to do what he wants (without more information from the OP). That's why I suggested a LDO circuit.It would go as low as 1.2V and you would need a supply about 3 V greater than the actual output. So 28 V minimum for 24 volts to 1.2V out.
Should it be variable amplitude X to 0V or X to V+ (12 or 24) ???still seems like a poorly defined driver .
is it +/-30mA or +0/-30mA
or 0 to 30mA variable or just 0 to 24V variable p-p? @ 30ma
or Vol<1V and Vol=Vcc?