A type of bipolar transistor comprised of p-type semiconductor in contact with n-type semiconductor which in turn is in contact with a p-type semiconductor -> thus PNP. The transistor has three terminals, the Emitter, Base and the Collector. Current injected into the base controls the flow of current from Emitter to Collector enabling amplification and switching.
Questions tagged [pnp]
438 questions
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PNP pre-amplifier small signals study
It's always a pleasure to read this forum and this time I'm making the step to ask a question :) !
I'm currently working on a pre-amplifier for microphones based on a schematic seen in a famous sound console!
I'm currently having troubles to realize…
TooT
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PNP transistor won't enter cutoff mode
I need a transistor lesson that I could not find on the internet:
I have a standard GND-PNP-Load-(-20Vcc) arrange:
(The two resistors attached to the base are to form a divider - ignore the values).
Im struggling because if I leave the base…
Lucas BS
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PNP circuit - The Art of Electronics
I was reading the BJT section of The Art of Electronics on page 77 Figure 2.10.B.
Shouldn't the divider voltage sit at 14.4 V rather than 11.6 V? the opposite what the author mentioned. Since if 3 is in saturation, the base voltage of 3 should be…
Rocky79
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How to stop PNP transistor from triggering at power up
In a simple PNP switch circuit, any capacitance on the base will make the transistor turn on when the 24V (V1) is first applied. It'll stay on until the cap charges. I imagine there will always be some stray capacitance, especially if the transistor…
Thomas C.
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PNP load switching circuit that uses opposing PNP transistors
Background: This circuit uses two input signals to create a 0, 2.5, or 5V output signal that switches ON/OFF periodically to control for example an LED.
I saw a transistor circuit example that had opposing PNP transistors. What is the point of Q3?
zme
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PNP transistor circuit
When switch \$S\$ is at position \$1\$:
$$V_B = R_2 \mathbin{/} (R_1 + R_2)*V_{CC} = 30 \mathbin{/} 130*-20=-4.62\mathrm{V}$$
$$R_{TH}=100*30 \mathbin{/} 100+30=23.1\mathrm{kOhm}$$
$$V_{TH}-I_ER_E-V_{BE}-I_BR_{TH}=0$$
where \$I_B= I_E \mathbin{/}…
Timoo
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PNP biasing logic resistor configuration
I have a PNP transistor connected as follows.
I know that there is voltage divider between Vdd and Vin.
What is the logic behind this configuration of PNP?
What kind of state it tries to bias it into?
UPDATE:
lub2354
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using pnp transitors as a normally open switch
I am trying to design a circuit that has 2 LEDs and using one pin from a microcontroller "toggle" which one is on. The LEDs themselves are part of another circuit driven by the same microcontroller, and I want to be able to toggle specific LEDs to a…
Anton Yukovitch
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Trying to understand how this PNP works
I am new to electronics and still learning so please don’t be too hard on me
Here is the circuit I am trying to understand:
To control to top PNP transistor, there is an optocoupler and 2 resistors.
When the opto is off, the base of the PNP is in…
Dominique
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High Side Driver Array Against ULN2804 For Motor loads Such As UDN2981, TD62783, TPIC6B595
Building a circuit to drive a few DC motors with UNO, 74HC595 and ULN2804. I had no issues with coding, connections and timings.
Then I started searching for high side driver arrays to control polarity of motors individually. I can't go for an…
stark
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Converting earth signal to 5 V square wave
I am in the automotive industry. I am working on a little project, where the engine computer originally uses MOSFET to drive an earth to charge up an ignition coil, and by cutting the earth, it fires the spark into the cylinder.
I would like to…
Jin Zhou
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Calculation of base current
Could you tell me how to find Vd and Vb in the schematic please? Is the PNP in saturation or linear mode?
I found Vb, with Vbe = Vb - Ve, then Vb = Ve -Vbe.
To find the mode of the pnp, I need to find Ib, and so Vd. But I don't know how to find…
Tack
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pull to GND switch for PSU enable
I need a circuit to toggle an control line on a PSU. The existing control line turns the PSU OFF when pulled to GND, the PSU is ON when the control line is floating or between 2.5V to 5.5V. I want to toggle this from an external device that has a…
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2 answers
pnp sensor on raspberry
how do I hook a PNP sensor to a raspberry pi 3?
I know I need an A/D converter, and I've already got a MCP3008.
But apart from that, what else do I need?
The sensor output switches 24v or 0v, I also know I have to bring it down to 3,3V.
Thanks a lot…
Roberto Mack
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PNP switching voltages
I am trying to use a TIP2955 PNP as a simple switch for an amplifier circuit. (I know TIP2955 is overkill, but I have so many laying around). The amp requires 12V. My logic is 5V. PNP pinouts:
* Emitter connected to +12V
* Collector connected to amp…
Pål Thingbø
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