Hi everyone,
I have found the attached circuit in book and couldn't understand something:
Here, a tristate LED is used to indicate the direction and type of current flow. If V is a positive dc voltage, the device emits red light. However, if V is a negative dc voltage, the device emits green light. If a high-frequency ac voltage is applied, it appears as if the device emits a yellow light. The diode which is connected in parallel with the resistor R2 is used to provide reversed-voltage protection when the applied voltage exceeds the maximum reversed voltage. My question is, there's only one diode to protect the reverse bias of gree LED, how about the red LED? No protection for it?
I have found the attached circuit in book and couldn't understand something:
Here, a tristate LED is used to indicate the direction and type of current flow. If V is a positive dc voltage, the device emits red light. However, if V is a negative dc voltage, the device emits green light. If a high-frequency ac voltage is applied, it appears as if the device emits a yellow light. The diode which is connected in parallel with the resistor R2 is used to provide reversed-voltage protection when the applied voltage exceeds the maximum reversed voltage. My question is, there's only one diode to protect the reverse bias of gree LED, how about the red LED? No protection for it?
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