Zener siode

122

03:18:07

The voltage drop across the second resistor should be 6.8 volts. But it's not, why is this?

published 8 years ago

earlmott

8 years ago

Kirchoff

earlmott

8 years ago

Kirchoff's Law. There is no voltage drop across a zener if it is not turn on.

earlmott

8 years ago

Without the diode the voltage drop is over 2 resistors.

thebugger

8 years ago

Because the two resistors act as a voltage divider and it's exactly half the supply voltage. Since the supply voltage is 9V half is 4.5V, and the zener breakdown voltage is set to 6.8V. The voltage divider simply drops too much voltage for the zener to engage, and frankly at these current levels, a simple zener won't do the trick, you either need to minimise the load consumption to maybe around 20-30mA or to add an external transistor to handle the high current demand

thebugger

8 years ago

Increase the first resistor to around 110ohm and the second one to 1kohm ;)

tylermccord5

8 years ago

You guys are awesome. People like you are what make this app/site great. I simply clicked because i was curious, and thanks to you I learned as well.

Dwelfman

8 years ago

Thanks everyone!

add comment in editor

EveryCircuit is an easy to use, highly interactive circuit simulator and schematic capture tool. Real-time circuit simulation, interactivity, and dynamic visualization make it a must have application for professionals and academia. EveryCircuit user community has collaboratively created the largest searchable library of circuit designs. EveryCircuit app runs online in popular browsers and on mobile phones and tablets, enabling you to capture design ideas and learn electronics on the go.