Why does horizontal output transistor keep blowing?
Improper drive to horizontal output transistor (HOT). A weak drive might cause the HOT to turn on or (more likely) shut off too slowly (greatly increasing heat dissipation. Check driver and HOT base circuit components. Sometimes, the horizontal deflection is designed based on the quirks of a particular transistor.
What is horizontal transistor?
The horizontal output transistor (HOT) is a switch. It provides a path for current to flow through the flyback’s primary winding and horizontal yoke as shown in Figure 2. The HOT is switched on and off by a signal applied to the base. Because the this is a power transistor, a current drive signal is needed.
What is the function of horizontal section in CRT TV?
Its function is to isolate the oscillator and to provide drive power for the horizontal amplifier. It also matches the relatively high output impedance of the oscillator to the very low input impedance of the horizontal output stage, which is a high-power (about 25 W output) amplifier.
How do you test a transistor output?
Hook the positive lead from the multimeter to the to the BASE (B) of the transistor. Hook the negative meter lead to the EMITTER (E) of the transistor. For an good NPN transistor, the meter should show a voltage drop between 0.45V and 0.9V. If you are testing PNP transistor, you should see “OL” (Over Limit).
What is a vertical transistor?
In vertical transistors, the transistor channel is formed perpendicular to the substrate and the channel length is defined by the thickness of the organic layers.
How does a flyback transformer work?
A flyback transformer works by storing energy in the form of a magnetic field during the first half-cycle and then releasing that energy with reverse terminal voltage. The device uses a diode (also known as a flyback diode) to conduct and stop the energy transmission.
What is CRT explain with diagram?
A cathode ray tube (CRT) is a specialized vacuumtube in which images are produced when an electron beam strikes aphosphorescent surface. Most desktop computer displays make useof CRTs. The CRT in a computer display is similar to the”picture tube” in a television receiver.
What is damper diode?
Damper Diode: A diode implemented to reduce voltage spikes. The diode is normally positioned anti-parallel [cathode to collector, anode to emitter] across a Collector-Emitter junction of a transistor.
Can you test a transistor in circuit?
Potentially faulty transistors can be tested with a digital multimeter, but the type of transistor will determine the type of test used. If testing a Junction Field Effect Transistor, or JFET, you will need to use two 1000-Ohm resistors in addition to the multimeter.
What are output transistors?
Output transistors are added to provide extra current to drive a speaker. Large output transistors only have a small HFE current gain, therefore driver transistors are placed in front of the output transistors to increase to total current gain to approx 200.
What are vertical devices?
Vertical GaN devices are capable of switching at even higher frequencies and operating at higher voltages, which should lead to a new generation of more efficient power devices. “Vertical GaN devices are 90% smaller than silicon. The lower the capacitance, the greater the switching frequency.
What is the output of flyback transformer?
Flyback transformers are commonly used for output current below about 10 Amps and output power below about 100 Watts. Coilcraft offers standard, off-the-shelf flyback transformers with power capabilities ranging from a few Watts to up to around 120 Watts.