1N4733A 5.1V DO-41 Zener Diode

A Zener diode is a special kind of diode which allows current to flow in the forward direction like a regular diode, but also allows it to flow in the reverse direction when the voltage is above a certain value. This is known as the 'breakdown voltage'. That means you apply voltage across them, and when a preset voltage is reached, they start conducting. A common analogy is a 'pressure relief valve'. They have lots of uses, especially in safety circuits where you want to make sure a voltage signal doesn't exceed a limit that might damage the circuit.
This 1N4733A zener diode is set at 5.1V, making it ideal for protecting the inputs of a 5V circuit. specifically,  it has a minimum voltage of 4.845 V and a maximum voltage of 5.355 V, with a leakage current of 1 V and a test current of 49 mA.
Zener diodes are often used to stabilize and clip circuits.
The 1N4733A is a 5V Zener Diode, meaning it has a breakdown voltage of 5V.
Charactiristics 1N4733A Zener Diode
Nominal Zener Voltage: 5.1 V
Zener Voltage Tolerance is ± 5 %
Maximum Zener Impendace at 49 mA: 7 Ohm
Power Dissipation: 1 W
Maximum Forward Voltage at 200 mA: 1.2 V
Package - DO-41
Weight: 0.35 grams
Operating and Storage Temperature Range: -65 to +175 °C