![]() It needs to dissipate wattage is 7V x 1A = 7W. The voltage across the transistor (VCE)is 20V -12V = 7V. It needs to dissipate wattage is 5V x 1A = 5W. The voltage across the transistor (VCE) is 20V -15V = 5V. It is effectively a dropper resistor and must dissipate heat according to ohms law. The transistor of C is dropping the most voltage. At 1A the current.ĭo you know which transistor has the most heat loss? Or… It must dissipate or reduce it.ĭo you see an image? It is simple. The transistor-Q1 works look like a resistor. In this series pass transistor regulator. Of course, energy will be expressed by heat. It should reduce the loss of energy in the circuit to a minimum. The transistor- 2N3055 can power load current up to 2A. ![]() The circuit will induct them into the transient noise. The power supply has a stray magnetic field. R1 increases the stability of the load circuit.C3 is a 0.047uF decoupler capacitor to filter out the transient noise.C2 keeps the reference voltage to be stable better.C1 is a smoothing capacitor at an input.Thus, it has a much more stabilized output. The advantage of this circuit, we can use a tiny current to Zener diode and base of a transistor. Because the voltage of Base-emitter less, transistor Q1 works less too. So it keeps the output voltage to be a constant level. But the base-emitter voltage rises up, transistor Q1 works more. In general, the output voltage is low down. In the circuit, the transistor has a proper gain and changing of VBE help it. Since it is a power supply that regulates a certain power output. If using this material on another site, please provide a link back to my site.This voltage is still suitable for many loads using the 12V supply such as receiver radios. Web site Copyright Lewis Loflin, All rights reserved. All NPN Transistor H-Bridge Motor Control.LM334 CCS Circuits with Thermistors, Photocells.Constant Current Circuits with the LM334.Simple Circuits for Testing MOSFET Transistors YouTube.Issues on Connecting MOSFETs in Parallel YouTube.Why Your MOSFET Transistors Get Hot YouTube.Issues on Connecting MOSFETs in Parallel.Test Power MOSFET Transistors, Observations.Build a High Power Transistor H-Bridge Motor Control.More Power MOSFET H-Bridge Circuit Examples.IGBT Based High Voltage H-Bridge DC Motor Control.Arduino Controlled IR2110 Based H-Bridge HV Motor Control.H-Bridge Motor Control with Power MOSFETs.N-Channel Power MOSFET Switching Tutorial.Understanding Bipolar Transistor Switches.Driving 2N3055-MJ2955 Darlington Transistors.Tutorial Using TIP120 and TIP125 Power Darlington Transistors.ULN2003A Darlington Transistor Array with Circuit Examples.Basic Electronics Learning and Projects.An additional benefit is isolating the 23 volts on the base of Q2 form the 5-volt TTL logic. In plate 4 we have a power TIP120 Darlington driving an even higher power Mj2955 PNP transistor. Variations of the above circuits are used to construct H-Bridge motor controls, relay and contactor drivers, etc. In plate 3 we use a TIP120 NPN Darlington to drive a 2N3055 NPN power transistor. Plate provides the basic data for the TIP120 and TIP125 power Darlington transistors. While rated at 5 Amps collector current they can provide the needed current gain and voltage isolation for the PNP Mj2955. We must have a pre-driver.Īn excellent choice for a pre-drivers for both the 2N3055 and Mj2955 are the TIP120 and TIP125 complementary Darlington power transistors. The low hfe of 20 means we require a base-emitter current of at least 500mA - far above the limit of most micro-controller I/O pins limited to 20-40mA. This problem is illustrated in plate 2 with the 2N3055 driving a 10 Amp DC motor. ![]() Plate 2 2N3055 transistor switch must have pre-driver. That means they can be directly connected to micro-controllers due to high drive currents required and in the case of the MJ2955 high voltage on the base can't connect directly to 5-volt TTL logic. They can carry an impressive 15 Amps of collector current making them ideal for high power switching applications such as motor drivers for use in power inverters.īut they suffer two problems that plague most high-power bipolar transistors - low hfe or DC current gain. Using Darlington Transistors Driving 2N3055-MJ2955 Power TransistorsĢN3055 (NPN), MJ2955 (PNP): Complementary silicon power transistors are designed for general-purpose switching and amplifier applications. Plate 1 2N3055-Mj2955 Complementary silicon power transistors.
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