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Questions tagged [pnp]

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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.

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I recently built a transistor curve tracer on a breadboard with my Oscilloscope and Arbitrary Waveform Generator. Most BJT Si transistors (NPN and PNP) show typical/normal traces but one device under ...
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Im new to Sziklai pairs and could not find any information on how to do calculations for this case. Im trying to do DC calculations and the info i have : +IN and -IN are for AC source, the +VE and -VE ...
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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). ...
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I am trying to implement a current mirror as part of a bias circuit for a RF amplifier. I want to do a transfer function of the bias circuit since it creates a loop from the amplifier fet drain to ...
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I'd like some insight to make sure my circuit's design is at its best. At the moment the circuit is working, but since this is my first time designing a circuit from scratch with transistors, I ...
Organ Bender's user avatar
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Let's say I want to add a L1C1 filter to power supply of PNP oscillator to avoid a current spikes drained from battery. In case of NPN circuits the designers usually place the L1 to Vcc rail. However, ...
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I found this reverse polarity circuit that uses a matched PNP pair and a MOSFET: https://projects-raspberry.com/raspberry-pi-b-power-protection-circuit/ I tested this circuit and with no load i get ...
Geologic's user avatar
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I have to find the input impedance Zi of the following circuit: Using the small signal equivalent for the transistor, I get the following schematic: It is easy to see, that we need to write the ...
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I understand that R1 and R2 make a voltage divider. initially Q1 is not conductive, so is Q2? initially C1 acts as short circuit, so flashes the light L1 for a moment? Please correct me if wrong. ...
Coppers Copernicus's user avatar
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This is simple simulation below of an NPN transistor: In the above transistor, without giving any base voltage, whatever voltage I give at the collector of the transistor, I am getting at the emitter....
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Edit: As you can see in the comments, I got a great explanation about the pull-up resistor question. I also wanted to make more of a bullet point of the PNP question as follows: When it comes to ...
Fixer69's user avatar
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I'm using PNP transistor to be a switch for CC pin of 7Segment (Common Anode) led and trying simulating it on Proteus at first. Something weird happens is that no matter high or low level at B gate, ...
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I've been given the following simple pnp transistor circuit where β=20 and Veb=0.7V and I'm trying to find the emitter current: I have the solutions but they don't agree with my results. My attempt: ...
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The textbook I currently read defines cut-off for PNP germanium transistors like this: For germanium transistors, however, cutoff for switching purposes will be defined as those conditions that ...
Allen's user avatar
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I am trouble shooting a power window amplifier circuit board for a Nissan Quest. The circuit board is relatively small, it has a few active component, most of which can be identified by simply ...
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I have built this circuit on a veroboard, and it seems to me that it has been wired correctly. I do however get a very low output from the circuit, approx 1/2 to 1/3 of the input signal. I reckon that ...
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Problem: How can the attached circuit be optimized so that, over a temperature range of -50°C to 150°C, the short circuit detection threshold lies between 5 V and 9 V? Requirements: The circuit is ...
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In the 1'st picture below I provided the amplifier circuit diagram. The 2'nd picture is showing the base signal of Q5 (green colour) and Vce signal of Q5 (blue colour). It is working as it is expected....
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I have a switch and want to read digital input pull up state from arduino. how can the key open the pc 817 optocoupler and trigger the pnp gate to read inputpullup pin from digital arduino. That ...
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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? ...
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What should be the output or purpose of below circuit (which is a part of EV inverter circuit).
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I'm working on a voltage-controlled crossfader. The schematic is taken from this thread on the electro-music forum. It's a simplified version of Thomas Henry's VC crossfader. I've been experimenting ...
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I built a ham radio amplifier kit that takes about 5 watts drive and makes 70 watts. It is called a MiniPA70. Here is a website someone put together describing its build/use. http://pa-11019.blogspot....
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I have a Peavey PV8 USB Mixing console which doesn't turn on anymore, the problem is a burned PNP switching the +15V rail. The Marking of the transistor is B1241 but due to the 3-SIP package im pretty ...
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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 ...
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In this circuit, I found out the wrong value for V_E. I calculated I_B with KVL around the 5V source loop and I got I_B = 2.25E-4 A then I calculate I_E = (beta + 1)*I_B = 9e-3 A and V_E = 10 - 4k * ...
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EDIT: I have added the drawn circuit. The LED (here) is 1W @ 3.4V so pulls about 300mA. I was hoping I could get somewhere close to that. Thanks. I am following an online course and struggling to get ...
no_entropy's user avatar
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In the attached image, OUT1 and OUT2 are logically identical (provided for redundancy). I'm wondering if it's valid for OUT1 and OUT2 to be tied together and brought across a single load? This is ...
Basic Questions's user avatar
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I have created simple light dector. Schemea is below: Real circuit on breadboard: I have written code in python using GPIO library: ...
Krzysztof Michalski's user avatar
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I've got an exact circuit diagram of the circuit in NPN, but I need to convert it to PNP. Could someone help, please? I've got a 2N2907 with me right now and I want to make my High Level trigger into ...
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I am studying for my circuits exam and in the review we have this question below: The output of a PNP transistor used as a switch is normally taken off it’s ____________ terminal. I would say ...
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I have a homework question but no idea what this circuit does and how to make calculations. In the simulation input and output voltages are same why? Thanks for any help
oggy's user avatar
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I have Biased the transistor Q1 in active region as shown in the following diagram. I have Sensor which outputs 1-10ma and needs to be connected across parallel as per the following diagram. the ...
Ronnie's user avatar
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I have build a latching circuit using both a NPN & PNP BJT to turn on and off an LED, as shown below: simulate this circuit – Schematic created using CircuitLab When I built the circuit and ...
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At the moment I implemented a current source with two FMMT560 for about 1 mA. These types allow -500V Vce. I expect startup peaks of 520 V which is too much. Are there any current sources which use ...
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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 ...
stark's user avatar
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I have a circuit with 2 PNP transistors, probably one of these is broken. One of these tested gives me a diode between Collector(+) and Base(-) while open circuit if I change the polarity of the test. ...
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The following transistor circuit section(using a PNP transistor BC557B) is inverting and buffering a 25kHz PWM pulse train coming from one of the Nano's PWM supported digital pins. The following is ...
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What does the constant ɣ represent in the following carrier motion of an PNP transistor? So I see three components for the base current. 1) According to the illustration I can see that some of the ...
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I'm looking for a circuit that I can add to a universal Input board that will be able to handle a 5-24v input PNP or an NPN 0v signal that I can connect to my arduino. I was considering using an ...
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Hi I am trying to switch on a brake light with a reed switch. The load is a 12v (0.1A) LED bike light. The following circuit works in the sense that the light comes on when the magnet moves away from ...
user1247060's user avatar
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I am new to biasing and have trouble finding the transconductance \$ g_{m1}' \$ for this biased differential amplifier below. I know that \$ V_{BE} = 0.6\$ V and \$ g_{m1}' = \frac{I_c}{V_T} \$ but ...
Clone's user avatar
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I am trying to build the following exponential converter circuit from the Thomas Henry "Making Music with the 3080 OTA" document. simulate this circuit – Schematic created using CircuitLab I ...
Dave Guenther's user avatar
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I am facing an issue while driving a four digit 7 segment display using a TI MSP430 MCU. Some digits are overlapped. Below is the code we are using: ...
JP Electronics's user avatar
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I'm wanting to drive a NeoPixel from a CMOS device. The power for the neopixel is a 4v LiPo battery and will fall from around 3.9v to 3v before it cuts off. I have a few PN2222 NPN transistors, I'm ...
reconbot's user avatar
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Due to reasons and curiosity, I want to know if I can recreate this circuit using NPN transistors instead of PNP transistors. I know functionally that they can be the same if we invert the polarities; ...
Wingmore's user avatar
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1 answer
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I want to control several SMD-LEDs (0603) 3.5V - 25mA, using a voltage source of 4V. Each LED needs a resistor of ~20 Ω to work fine, like shown in the circuit below: simulate this circuit – ...
Rogutin's user avatar
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I took apart a flickering LED candle. The circuit oscillates at 1 Hz verified with multimeter and oscilloscope. Can anyone explain how the circuit works? It looks like the emitter is grounded in a ...
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I have a question regarding Schmitt Trigger. I am trying to design an inverting output (at UTP=Low, at LTP=High) Schmitt Trigger for an application. However, I need to use PNP transistors since the ...
Mert Karadeniz's user avatar
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I need to switch off a PNP transistor however, the voltage on the emitter side will always be larger than the base. Is there a way to switch the transistor off? Edit: The aim is to maintain a constant ...
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