Diode Configuration in Protection Circuit: Nose-to-Nose or Tail-to-Tail?

In summary, The speaker is replacing a switch in a piece of equipment and has noticed a discrepancy between the circuit diagram and actual circuit regarding the wiring of the diodes. They are wondering if there will be a significant difference between the two configurations and are seeking clarification on the purpose of the midpoint of the diode connection. Another speaker explains that the diodes are zener diodes and confirms that both configurations will limit the difference between HI and LO to approximately +/- 12.5 volts.
  • #1
nbo10
418
5
Hi All,
I'm replacing a switch in a piece of equipment. I'm looking at the circuit diagram and the actual circuit, and I notice that the diodes in the circuit aren't wired as they are in the diagram.:rofl: The HI signal is dc from 0-1 Volt and LO is ground. Is there going to be any significant difference between the two? I think they do the same thing, but in the real circuit one of the diodes is going to be conducting. While in the diagram neither of the diode are going to be conducting.
 

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  • #2
I don't understand the drawings. What does the midpoint of the diode connection go to? Usually diode clamps to the rails have a diode up from GND to the circuit to be protected (anode side to GND), and a diode up from the circuit to the + supply (with the cathode connected to the + suupply). That way, positive transients on the circuit will be clamped at the + supply plus a diode drop, and negative transients will ce clamped at GND minus a diode drop.
 
  • #3
The midpoint of the diodes goes nowhere. the diodes are zener diodes. If I understand correctly both circuits limit the differenece between HI and LO to +/- 12.5 volts. Is that correct?
 
  • #4
If they're about 12V zeners, then yes, the configuration with nose-to-nose or tail-to-tail zeners will clamp at about 12.6V at room temperature.
 

1. What is a diode protection circuit?

A diode protection circuit is a type of electronic circuit that is designed to protect a device or circuit from potential damage caused by excessive voltage or current. It uses diodes, which are electronic components that allow current to flow in one direction, to prevent reverse polarity and overvoltage situations.

2. Why is a diode protection circuit necessary?

A diode protection circuit is necessary to prevent damage to electronic devices or circuits. Without it, reverse polarity or overvoltage situations could occur, which can cause the device to malfunction or even permanently damage it. A diode protection circuit helps to ensure the proper functioning and longevity of electronic devices.

3. How does a diode protection circuit work?

A diode protection circuit works by utilizing the properties of diodes to allow current to flow in only one direction. In a reverse polarity situation, the diode will block the current from flowing through the circuit, preventing damage. In an overvoltage situation, the diode will act as a voltage regulator, limiting the amount of voltage that reaches the device or circuit.

4. What are the types of diode protection circuits?

There are several types of diode protection circuits, including transient voltage suppression (TVS) diode circuits, zener diode circuits, and Schottky diode circuits. Each type has its own unique characteristics and is used in different situations depending on the specific protection needs.

5. How do I choose the right diode protection circuit for my application?

The right diode protection circuit for your application will depend on the specific needs and requirements of your device or circuit. Factors to consider include the voltage and current ratings, response time, and type of protection needed. It is important to consult with a knowledgeable electronics professional to determine the best diode protection circuit for your specific application.

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