# Tag Info

Accepted

### What is this unusual NPN-PNP transistor pair?

These transistors are devices which are highly optimized for use in ultra-low-cost and high-volume consumer products- off-line fluorescent lamp ballasts. The anti-saturation network (for fast ...
• 328k

### My teacher said a BJT phototransistor doesn't have a base

I think you and your teacher are both right - you are just not using the same definitions and thus your wording disagrees. From your description: Shouldn't be transistor without base be just a ...
• 12.1k

### 'Leftover' voltage when using constant current

This circuit is particularly useful for a variety of reasons. So I wanted to do it a little more justice than just two sentences' worth. OVERVIEW In the following circuit, I've intentionally boxed up ...
• 69.1k

### When is a MOSFET more appropriate as a switch than a BJT?

When is a MOSFET more appropriate as a switch than a BJT? Answer: 1) a MOSFET is better than a BJT when: When you need really low power. MOSFETs are voltage-controlled. So, you can just charge ...
• 1,200
Accepted

### Why do CMOS NOT gate designs differ from BJT NOT gate designs?

However, I've always been perplexed as to why people do not use the former method for chip manufacturing. In chip design, resistors take up more area than transistors, and area is one of the main ...
• 121k
Accepted

### What's this driving circuit of LED?

As Ignacio Vazquez-Abrams mentions it's a constant current driver though the designer put the switch in the wrong spot. Theory of operation with these drivers is the LED current path is through the ...
• 45.7k
Accepted

### Why have both: BJT and FET transistors on IC output?

Paragraph 2 of the description says: FAN3100 drivers incorporate MillerDriveTM architecture for the final output stage. This bipolar-MOSFET combination provides high peak current during the Miller ...
• 159k
Accepted

• 6,961
Accepted

### How does this BJT transistor circuit works?

The zener with series resistor R3 has about 10V on the anode wrt ground. It is seeing 50mA so the actual voltage will be a bit higher than the 10V nominal, maybe one percent on average. That voltage ...
• 328k
Accepted

### Why so many variations of BJT transistors

In the early days of BJTs, every year the processes would improve and there would be new applications for these parts with new demands. As a result, semi-conductor companies were frequently coming ...
• 306k

### Understanding class A amplifier waveforms

In active mode operation, the BJT collector will be 180 degrees out of phase with the base. But when the BJT is saturated, its collector will tend to follow the base when the emitter resistor is ...
• 69.1k
Accepted

### A question about relaxation oscillator

Collector-emitter breakdown voltage isn't the relevant parameter in this circuit. Note that the B-E junction is reverse-biased, and the B-C junction is forward biased, so the relevant parameter is ...
• 164k