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| lab05_en:inverting_op-amp_photo_diode_as_current_source [2026/04/27 13:47] – mexleadmin | lab05_en:inverting_op-amp_photo_diode_as_current_source [2026/05/07 12:37] (current) – mexleadmin | ||
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| === Photodiode as current source === | === Photodiode as current source === | ||
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| + | A photodiode is a special type of diode which, **in the absence of light**, exhibits a **current-voltage relationship** very similar to that of a standard diode (see the **dark current** characteristic in the **\(I-V\) diagram**).\\ | ||
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| + | **When illuminated**, | ||
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| + | Photodiodes are often operated **in reverse bias**, **where** the charge carriers (electrons and holes) generated by the incident light cause an increased **reverse** current flow (**third quadrant** of the I-V diagram). The higher the light intensity, the greater the reverse current. **Forward bias operation** is also possible, where the photodiode behaves like a solar cell (**first quadrant** of the I-V diagram). | ||
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| + | **Applications include** remote controls (IR range), galvanic isolation (optocouplers), | ||
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| + | {{drawio> | ||
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| Complete the arrows in the circuit diagram in <imgref Fig-100_inverting_op-amp_photo_diode> | Complete the arrows in the circuit diagram in <imgref Fig-100_inverting_op-amp_photo_diode> | ||
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| Calculate $R_{\rm 2}$ so that $U_{\rm OUT}$ = 5 V at 300 lx. | Calculate $R_{\rm 2}$ so that $U_{\rm OUT}$ = 5 V at 300 lx. | ||
| Take a resistor from the E6 series that is as close as possible to the calculated value.\\ | Take a resistor from the E6 series that is as close as possible to the calculated value.\\ | ||
| Also enter the values for $I_{\rm 1}$, $I_{\rm 2}$, $U_{\rm 2}$ and $U_{\rm OUT}$.\\ | Also enter the values for $I_{\rm 1}$, $I_{\rm 2}$, $U_{\rm 2}$ and $U_{\rm OUT}$.\\ | ||
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| {{drawio> | {{drawio> | ||
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