The relationship between worst-case rise time and load resistance for the basic phototransistor circuit indicates that for a T_R of 42 μsec, R_LOAD should equal 7.5 kΩ

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Other Materials from the Main Document

• Article «Circuit optimizes phototransistor bandwidth»
• Figure 1. A basic phototransistor (a) has a 5- to 8-μsec rise/fall time with a 1-k. resistor. An op amp can improve a phototransistor's response time (b) but performs poorly without additional phase compensation. Alternatively, you can use a transistor to isolate t
• Figure 2. The relationship between worst-case rise time and load resistance for the basic phototransistor circuit indicates that for a T_R of 42 μsec, R_LOAD should equal 7.5 kΩ