0.25 to 0.3 V

Signal Diode Parameters

• Maximum Forward Current. The Maximum Forward Current ( IF(max) ) is as its name implies the maximum forward current allowed to flow through the device.
• Peak Inverse Voltage.
• Total Power Dissipation.
• Maximum Operating Temperature.

A Germanium Diode has a voltage drop of approximately 0.3V across its leads. A diode is a device that drops a specific voltage across its terminals. It is necessary that a diode get this voltage so that the diode can conduct.

Typically at room temperature the voltage across the depletion layer for silicon is about 0.6 – 0.7 volts and for germanium is about 0.3 – 0.35 volts. This potential barrier will always exist even if the device is not connected to any external power source, as seen in diodes.

Why is silicon usually preferred to germanium in the manufacture of semiconductor devices? Silicon is abundant on the earth’s surface and therefore cheaper than germanium. The PIV (Peak Inverse Voltage) rating of silicon is much higher than germanium and therefore can withstand much higher temperatures than germanium.

Silicon Diodes, LED’s and Boltzmann’s Constant A diode is a widely used two-terminal circuit element that minimizes current flow in one direction (reverse bias), while easily carrying current in the other direction (forward bias). A semiconductor material that changes abruptly from p-type to n-type has this property.

A diode is a semiconductor device that essentially acts as a one-way switch for current. It allows current to flow easily in one direction, but severely restricts current from flowing in the opposite direction.

A single diode can transform AC power into an intermittent DC flow, but a bridge rectifier uses four diodes to reverse the direction of both sides of the AC pulse. With a bridge rectifier, the DC still oscillates from zero to a peak value, but it doesn’t cut out half the time.

A bad (opened) diode does not allow current to flow in either direction. A multimeter will display OL in both directions when the diode is opened. A shorted diode has the same voltage drop reading (approximately 0.4 V) in both directions.

Schottky diodes are used for their low turn-on voltage, fast recovery time and low-loss energy at higher frequencies. These characteristics make Schottky diodes capable of rectifying a current by facilitating a quick transition from conducting to blocking state.

Forward Current The maximum that the diode can conduct at once is 30 amperes. However; if the diode is required to conduct that much current at once, the diode will fail in approximately 8.3 milliseconds.