Power Amplifier

Now you can protect your HiFi amplifier from damage due to overheating. This circuit will cut off power to the amplifier board at the time the temperature was high. Automatically connect the power when the temperature returns to normal. This circuit uses a sensor NTC Thermister heat and also has a warning sound and reset determination. Amplifier circuit protector is using popular timer IC NE 555 as the temperature controlled switch. The trigger pin 2 is connected to a potential divider consisting Thermister VR and NTC. Thus the voltage on pin 2 depending on the resilience and determination Thermister VR. NTC (Negative Temperature Coefficient) Thermister has a high resistance in the normal temperature and the resistance decreases as temperature increases. Threshold pin 6 of IC is used to reset the IC if necessary. When the pin 6 voltage gets higher than the IC pin 2 will reset and the output is low. Power Amplifier Protector  Circuits Power to the amplifier board is given by (NC)...

Vertical Protectors (another term surge protector or Vertical CRT Neck Guard or protector) . If the vertical deflection does not work, then the raster will glow a horizontal line. This can cause the picture tube phosphor layer was destroyed by fire when the aircraft be kept alive in the long term. There are several types of system protectors, vertical relationships: Protector surge protector is connected with x-ray to the horizontal which will trigger the horizontal oscillator is not working Protectors gets connected to microcontrol that will trigger the "power off" so that the plane will turn off automatically or plane alive but raster becomes dark (brightnes level down). Vertical Protect The workings of the system-vertical surge protector that can be found there are several kinds: Using sampling pulses from vertical-out IC which is connected to  microcontrol  . If  microcontrol   not receive these pulses the surge protector will work. Using a sampling of...

PKC-136 PEAK CLAMP CHARACTERISTICS VBR 160Vdc VDRM 700Vdc P 1.5W . See Circuits Diagram below : Protection of the Mosfet in flyback power supply    Feature : - Protection of the Mosfet in flyback power supply -  TRANSIL™ and blocking diode in a single package BENEFITS - Accurate voltage clamping regardless load - Reduced current loop - Reduced EMI emission - High integration - Fast assembly - Reduced losses in stand by mode

Lightning Protection ELCB (CIRCUIT BREAKER Earth Leakage) Installation of a building usually equipped with a safety short circuit current and current limiters. In the event of a short-circuit the safety fuse will break, and when the series occurred over the current-limiting load (MCB) will open the circuit so that circuit current flow to the inside of the building to be disconnected. If it occurs in an electrical installation safety is a leakage current and current-limiting fuses can not provide security so that the power loss will occur continuously. Apart from that, if there are power users have a leakage current and untouched by humans, the safety will not be decided so that the electrical circuit is quite dangerous it would be safe if the installation is already installed grounding. But when man-voltage electrical power users then all these safety devices can not be secured. For that installed a safety device, called an Earth Leakage Circuit Breaker or ELCB. This tool is able t...

Toggle switch in this article is a series of toggle switches that are controlled by infrared light. The series toggle switch is made from a combination of data flip-flop CD4013 2 units. Receiver circuit of the infrared light signals arranged with infrared receiver as found on television remote receiver. Infrared signal from remote is used as clock signals and data to the data flip-flop first. then the second flip-flop data set as a toggle flip-flop toggle the output signal is used to drive the relay. for more details can be seen in thethe following image . Series Toggle Switch With Infra Red (IR) that is required to supply voltage range of 12VDC and the output of Toggle Switch With Infra Red (IR) is dapt used to turn on the lights or other electronic devices with DC or AC voltage source. Series Toggle Switch With Infra Red (IR) was isolated from the load that is placed for use as the final relay. source [ link ] 

RF amplifier protection I have developed the protection circuit for the EB104 amplifier I am working on, after I finally had some time to design and test a few models. The main requirements have been: - protection in case of high temperature; - protection in case of high SWR; - protection in case of wrong output filter selection; - simple design (i’m a fan of the whole K.I.S.S. rule of thought), able to work in strong electromagnetic fields, reliable, inexpensive. Because i will be using the same directional coupler i have used in the SWR meter (the one made on PCB) wich is directly influenced by the signal frequency, and because i want full HF coverage, i cannot just measure the reflected signal and make a circuit cut the amplifier when it goes over a limit; on 28Mhz the coupler generates roughly 4 times more voltage that let’s say in 7Mhz. So a system that compares direct and reflected signal and triggers when the latter is percentually too high was needed, therefore an operational a...

Basic circuit of the LM35 are made to control the fan is either used on amplifier that requires automatic cooling. Its use on power amplifier circuit above and only requires DC fan. From basic sensors based on ic and amplifier op-amp is added again to the transistor Q1 to drive the fan. Part List : R1___220K R2___100K R3___3K3 R4___22K R5___1M R6___150R R7___2K2 R8___33R 4W C1___100pF D1___1N4148 IC1__7915 IC2__TL072 IC3__LM35 F1___DC Fan 12V

 This is basic of workmaship LM35 temperatur sensor, whish is taken from the LM35 spending and boosted again by the amplifier op-amp. High output if the sensor is received by ic LM35 high temperature . You can use the output as driver relay, fan , or other. And if yo want to see modifications LM35 temperature sensor see here.  

 Used as a protective circuit above uses a component named PTC , the components in the operating obstacles , but obstacles desert PTC component is influenced by temperature, whereby if the cold temperatures of less than 100 degrees celcius , then this component has a few obstacles. And when temperature run to 100 degrees celcius or higher, which is owned PTC resistance will rise ass well. Because it depends on ambitient temperature , the PTC can be assembled into a circuit protection if high ambitient temperature, tand automatically switchess off, circuit like a schematic above. Part List : R1___4K7 R2___10K R3___1K9 R4___1M R5___4k7 TH1__PTC thermistor IC____LM393

Circuit which is also equipped with temperature sensors would protect the high temperature. However, in the above circuit which necessiatated the input of the amplifier / audio signal. The way it works is , if the amplifier circuit to work and ouput signal to be connected to this circuit , Fan 12V will work well. If the received audio signal this circuit does not exist , then the fan 12V die. And automatic circuit amplifier also not work and does not require refrigeration. Part List : R1_________________220K R2,R9,R10,12,13_____100K R3_________________2K4 R4_________________22K R5_________________1M R6_________________150R R7_________________2K2 R8_________________33R 4W R11________________10K C1_________________100pF C2_________________47uF 25V C3_________________100uF 25V D1,D2______________1N4148 Q1_________________MJE350 Q2_________________MPSA42 IC1________________7915 IC2________________LM35 F1_________________Fan 12 Volt