The red and blue LEDs are driven by a long-tailed pair and controlled by pot (potentiometer) R4, whose wiper voltage varies according to its position and is used to control the green LED's drive, producing a decently wide spectrum
| Authors | Nick Cornford |
| Main Document | Article «A pot of many colors» |
| Description | Figure 1 |
| File Format / Size | PDF / 17 Kb |
| Document Language | English |
Other Materials from the Main Document
- Article «A pot of many colors»
- Figure 1. The red and blue LEDs are driven by a long-tailed pair and controlled by pot (potentiometer) R4, whose wiper voltage varies according to its position and is used to control the green LED's drive, producing a decently wide spectrum
- Figure 2. This graph plots the LED currents against pot rotation
- Figure 3. Rearranging the circuit and adding an op-amp to drive the green LED gives better, more linear control of the LED currents
- Figure 4. The response of the revised design has more linear curves, giving a smoother spectrum