Adding DC offset to Picoscope's SG

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Ruslan
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Adding DC offset to Picoscope's SG

Post by Ruslan »

I want to add DC offset voltage of 3.3V in series with Picoscope's signal generator. On the Picoscope it is written that the maximum voltage is -/+ 5V. In any case I want to ask is it safe to connect signal generator and power supply of 3.3V while not exceeding 5V on the output voltage.

Martyn
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Re: Adding DC offset to Picoscope's SG

Post by Martyn »

Which PicoScope model do you have ?
How are you proposing to wire up the supply and generator ? (a sketch would be good)
Martyn
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Ruslan
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Re: Adding DC offset to Picoscope's SG

Post by Ruslan »

Martyn wrote:Which PicoScope model do you have ?
How are you proposing to wire up the supply and generator ? (a sketch would be good)
Supply and generator are just in series like on the image attached. I need to power up the LED with the voltage between 2.8V and 3.1V in order to produce the light of different intensities. So I just wanted to set the value of power supply to about 2.9 V while varying the voltage of signal generator between -0.1V and 0.2V.
What's the maximum current (voltage of the supply) which can pass through signal generator without damaging it if I want to use more powerful LED.
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Martyn
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Re: Adding DC offset to Picoscope's SG

Post by Martyn »

You need to take care as the signal generator ground is connected to the USB and channel grounds, so any shift would need to be after the signal has been generated using a clamp and bias circuit.

For a more detailed discussion of possible options please email support@picotech.com
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MalcolmCaemmerer
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Re: Adding DC offset to Picoscope's SG

Post by MalcolmCaemmerer »

I've just set up a Diode Clamping circuit together with my PicoScope 3203 to generate a 0-3.6V pulse from the Signal Generator. The output was fairly low current but it was enough to drive a fiber optic transmitter for 188µs using a 900nF capacitor and a 10kOhm resistor. This was sufficient as I'm driving a pulser unit for about 200µs with a duty cycle of 24Hz using the fiber optic connection.
As I'm not an electrician this website helped me:
www.circuitstoday.com/diode-clamping-circuits

Malcolm

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