Identify zener diodes.
Key and critical concepts which you will learn:
- You will be learning towards the outcome “Identify zener diodes.”
Whilst learning towards the outcome you will be required to achieve the following:
- Identify zener voltages.
- State in which direction a zener diode is connected in a circuit to act as a voltage regulator.
- Draw the circuit symbol for a zener diode.
- Draw a curve of the forward voltage (VF) against current (IF) for a zener diode.
- State the reasons why a series resistor (RS) is connected in a zener parallel voltage regulated circuit.
- Draw a characteristic curve for zener voltage (VZ) against current (IZ) for a zener diode.
- Draw a IZ/VZ characteristic curve for the operating range of a zener diode and show all the calculations made.
- Draw a circuit diagram showing how different voltages may be obtained from a common supply by means of zener diodes.
- State what the effect would be if zener diodes were connected in series.
- State what the effect would be if zener diodes were connected in parallel.
- Draw a waveform indicating peak voltage, when the voltage is “clamped” with zener diodes.
Tools, consumables, machinery and equipment required:
- Small sidecutters
- Soldering iron
- Soldering wire
- Resistors (100 Ohm ½ W, 1K ohm ½ W, 2 x 150Ω ½ W, 10K, 4K7, 2K2, 1K, 470Ω, 330Ω, 220Ω).
- Variable AC supply
- Variable DC supply
- Zener diodes (5V 1W, 7.5V, 9V, 10V 1W, )
- 1N4007 diodes
- Bridge Rectifier (50V 1A)
- 2200 uF Electrolytic capacitor
- Circuit board
- Connecting wires
- De-soldering pump
- Zener diodes are used as voltage and shunt regulators.
- Electrical Technology Edward Hughes.
Pages 578 and 579.
- Electrical Trade Theory C. du Preez.
- Semi-conductor Reference Book.