With a 4k1 collector resistor and 16mA drive into the led, the chosen (read ‘cheapest on ebay’) 6N135 is supposed to beat 1.5μs for both turn on and turn off, with typical figures of 90ns and 800ns.

[Paulo] just tipped us about an Excel based high frequency transistor amplifier calculator he made. We’re guessing that some of our readers already are familiar with these class A amplifiers, commonly ...

This simple Mock Flasher LED simulates the indicator of a sophisticated Alarm system. It can be placed in doors, gates and vehicles to confuse intruders. The circuit is too simple using a Unijunction ...

Light-emitting diodes (LEDs) are often used with a voltage source from a power-supply output voltage. The output voltage increases until the current through the LEDs reaches the value of the ...

Signals when an on-circuit battery is exhausted, 5V to 12V operating voltage A Battery-status Indicator circuit can be useful, mainly to monitor portable Test-gear instruments and similar devices. LED ...

Two of the most often used amplifier building blocks in audio amplifier design are the common emitter amplifier with emitter degeneration and the emitter follower using the same circuit biasing. The ...