How does a transistor behave in 3 modes?
Cut-off — The transistor acts like an open circuit. No current flows from collector to emitter. Active — The current from collector to emitter is proportional to the current flowing into the base. Reverse-Active — Like active mode, the current is proportional to the base current, but it flows in reverse.
Which a PNP circuit the most positive voltage is probably?
20. With a PNP circuit, the most positive voltage is probably: A….Exercise :: Bipolar Junction Transistors (BJT) – General Questions.
| A. | 16.80 |
|---|---|
| B. | 1.05 |
| C. | 0.20 |
| D. | 0.95 |
Can a transistor turn off a 3.3V GPIO?
The transistor is a PNP type so you need to apply close to +5 to get it to turn off. You can do this with one transistor and a couple 10K resistors, as shown. The circuit will work with 0/3.3V input (anything from a bit over 1V to more than 10V is an acceptable ‘1’, and < 200mV is ‘0’).
What happens when the PNP transistor is turned on?
The protection diodes on most logic chips creates a sneak-path to positive supply. This will keep the PNP transistor permanently turned on and may damage the chip. In your case your micro is powered from +3.3 V and Vss is +5 V. The result is the same, as you have discovered.
How to turn off NPN transistor in GPIO?
A simple check of the circuit with an ohm meter should be able to confirm how the LEDs are connected. The schematic is probably like this – inside the dotted box (ignoring the LEDs). The transistor is a PNP type so you need to apply close to +5 to get it to turn off. You can do this with one transistor and a couple 10K resistors, as shown.
Can a p-channel transistor control a 5V rail?
There is a standard way to do this with a P-channel MOS transistor (PMOS). This is the standard way of doing it. You may or may not need to add C1. If the load has capacitance, then sometimes when you turn on M1, the 5V rail will suddenly dip, and that can cause problems for anything powered from 5V.