An optocoupler or an optoelectronic coupler is basically an interface between two circuits which operate at usually different voltage levels. Here are other circuit configurations to interface with ttl circuit, specifically the 7400 family. I would build the first circuit posted, and not worry about the isolation. Relay and optocoupler electronics forum circuits, projects. Emgov power opto couplers are used as the modular interface in all industrial fields for signal amplification to 230v 3a and for electrical isolation. While working with high power amplifier designs, two things become crucial, the protection of the amplifier and the protection of the speakers from an accidental over current influx. Linear opto isolator circuit electronic projects circuits. Relay module 1 no high level 6 mm spacing relay mod. The amp is basically stuck in the quiet part of the tremolo cycle. The figure 14 circuit s optocoupler phototransistor is wired between the input and ground of the driven righthand ttl ic because a ttl input needs to be pulled down to below 800mv at 1. It turns out i wasnt alone as the amp was first announced, many of the early buyers were already fans of vox. You need a solidstate relay, which has an opto coupler builtin. The circuit as drawn will not work, i would also advise you, use a transistor driver after the opto. An optocoupler effectively isolates an output and input circuit.
Or, you could control a suitable power device with an opto coupler. An optocoupled solidstate relay contains a photodiode optoisolator which drives a power. For demonstrating the working of this relay module, we have used. They galvanically isolate the low and highvoltage sides of a circuit by using an infrared emitter to transmit the control signal to a photo detector and reduce. How to connect a relay through an optocoupler homemade. I figured that the logic gets inverted when i used the gpio as the source voltage for the optoisolator led.
This vox circuit can be used to operate a tape recorder, ham radio, cb radio, or turn on an alarm. Cmos ic outputs can source or sink currents up to several ma with equal ease. Review ac relay circuits optocouplers triacs youtube. In circuit we use the opto compiler ics number of moc 5010 as a base. I can get the lt9914 but by all accounts this seems to be unreliable i have also tried to locate the suggested replacement vlt5c3 but cannot find reference to it from any of my usual suppliers farnell, rs. Optocoupler, phototransistor output, ac input, with base. For example, separate the circuit from the power line, send an audio signal, electronic medical, etc. With an optocoupler, the only contact between the input and the output is a beam of light. The cambridge 15 is a small hybrid 1x8 15 watt combo amp that was introduced by vox in 1999. In this application you could isolate the thyristor controller with a. Quick and simple elementary relay replacement after a failure. Learn how an optocoupler works to safely separate highvoltage components and lowvoltage devices while removing electrical.
The phototransistor can be used to switch current in the output circuit. The vox cambridge 15 is a small hybrid 1x8 15 watt combo amp that was introduced by vox in. A opto isolator is appropriate, but no, you dont just wire 120 v into one. The circuit design for channel two was a blend of transistorized and tube circuitry. Controlling relay with optocoupler, resistor confusion avr. How an optocoupler works and example circuit duration. As we know, a diode is required to protect the circuit from the reverse current inducted from the coil when power off the relay. In this video, ive explained how to make an optically isolated relay driver circuit by using an optocoupler, here ive used pc 817. When the opto coupler bulb fails in the traditional tremolo circuit, the amp continues to operate at normal level, only the tremolo stops working. Before studying the proposed design, lets first understand how an opto coupler works. It has all the vox cosmetics, including gold string in the cabinet sides, top, and bottom. How to make an 8 channel relay driver board optically.
Elegoo 8 channel dc 5v relay module with optocoupler. Any sound will be captured by the microphone and will activate the output relay which will remain activated while there is sound. Jul 18, 2018 optocoupler circuit vs relay circuit rick loresto. You would also need a suppression diode across the relay coil to protect the transistor. Optocoupler, phototransistor output, ac input, with base connection h11aa1 vishay semiconductors description the h11aa1 is a bidirectional input optically coupled isolator consisting of two inverse parallel gallium arsenide infrared leds coupled to a silicon npn phototransistor in a 6 pin dip package. To have 1ma opto transistor collector current vertical line according to that figure i need to have led current about 1ma if. An opto coupler is a device which encapsules an led and a phototransistor inside a hermetically sealed, water proof, light proof package in the form of an 8 pin ic resembling a 555 ic. You need a solidstate relay, which has an optocoupler builtin. The relays can switch currents in the range of nanoamps to hundreds of milliamps. Optoisolated 8 channel 5v relay module art of circuits.
This xvive vtl5c3 opto coupler can be used to repair several models of vox amplifiers in which the opto coupler used in the tremolo circuit has failed, resulting. The cambridge, of course, was also infamous for cambridgitis, which was caused by the choice of an inadequate stock. Relay drivers gate drivers are available at mouser electronics. Calculate the value of the led current and the value of current through the 3 k resistance. So, if the gain of the relay driver is 200 and, the gain of the transistor within the optocoupler is 10, the total gain is now 2,000. The nice part about this one is the isolation provided by the optoisolator. As my relay coil needs around 250 ma, i used a mps222 transistor. Oct 30, 2008 with r1 and r2 at those values, the opto transistor will always be switched on. Such fluctuations take hours to settle and can be only partially offset with feedback in the control circuit. The most distinct part of optocoupler as a switch is to isolate low voltage circuit from high voltage circuit. Voice activated switch vox1 electronic hobby kits from. Maybe a resistor divider to pad the audio going to the tx, thats all.
Vox cambridge 30 and pathfinder 15 repair optocoupler ebay. There is a simple test to determine if the cambridge. Basically, the gain of the one transistor is multiplied by the gain of the second transistor. If the optoisolator fails in the cambridge 30, the resistance in the photo resistor rises to the high limit for the part, causing the amp to severely lose power. The key advantage of an optocoupler is the electrical isolation between the input and output circuits. Replace the tube, upgrade the optocoupler to get the output stable again. Hi, i am trying to source an equivalent part for the optocoupler on the cambridge amp. That 5v relay supply could be totally isolated from the 3. Elegoo 8 channel dc 5v relay module with optocoupler elegoo inc.
Vox korg cambridge 30 and cambridge 30 twin modifications. Or, you could control a suitable power device with an optocoupler. Later vox models in the low to mid price range would drop this cosmetic touch. We have allowed a place on the pc board for you to supply a dip style relay. Types of relays and relay driver circuit buchholz relay. It has all the vox cosmetics right, including gold string in the cabinet sides, top, and bottom. The 3pin header on the left selects how your program. This is the linear opto isolator circuits that use a few parts and cheap. Optocoupler tutorial about how optocouplers and optoisolators use light to.
The vox cambridge reverb 30 and reverb twin used a 12ax7 in its gain channel, but in the preamp stage, as one would normally be used. This vintage vox cambridge 15 v9159 guitar tube combo amp is a rare find. When a supply voltage of 20 v is applied the led carries a current and 2 v is dropped across it. Typical isolating optocoupler applications include lowvoltage to highvoltage or vice versa signal coupling. Analog opto isolator this is a circuit to use a standard, low quality opto isolator to transfer an analogue signal with reasonable linearity and without complicated feedback loops to monitor and linearise it. Examplein terms of usage say a person wants to turn on 500 kw motor, he could simply. Too bad vox used one crappy component in a nicely concieved amp. This is a 5v 4channel relay interface module, for controlling various appliances, and other equipments with large current. Opto modules and solid state relays product information 2. Simple voxaudio activated relay circuit for 2 meter digi. I am controlling a relay with stm32 micro controller. Now i must find out the opto led current, which allows 1ma current in opto transistor. The circuit shown in figure 1 will drive the relay through optocoupler in same circuit with same power supply. You have not indicated what is the relay coil currentresistance.
If you want to have 1 ma flowing, you will need at least 5 ma flowing in the led. The most important reason is the coil in the relay is a pretty complex load in the circuit. Wagos 788 series relay sockets are ideal for switching applications in both industrial and process automation. In this 4channel relay driver circuit we have used an optocoupler whic his triggered by active low signal, to trigger the npn transistor which further drives the relay. The cambridge, of course, was also infamous for cambridgitis, which was caused by the choice of an inadequate stock optocoupler, which would fail when the amp was driven hard for 15 20 minutes. The diagram of figure 2 shows a bidirectional optocoupler input interface circuit. Here we have used 12v 10amp relay in this pcb board, but you can also use 5v relays. The vox showroom the v9169 vox cambridge 15 amplifier. After replacing that part the amp rocks if you have this amp or the cambridge 30 1 10 versionthats your fix. Jun 24, 2010 an opto coupler wont be able to switch a load like the relay. Assuming that it is an led type opto, 15ma or less sounds more reasonable. The input of a opto isolator is just a led, or sometimes two leds in parallel with opposite polarity.
Normally a low value resistor is usually employed at the output of mosfet amplifiers, the current developed across this resistor can be well exploited for tripping a relay in case it. Microopto solid state relays datasheet 376 kb download. Lt9914 opto coupler location next to tremolo speed control. Microseries class 1, division 2 approved relays 244 kb download. The circuit is designed to be compatible with most microcontrollers including avr8051picarm and boards such as arduino. An optocoupler is a device which encapsules an led and a phototransistor inside a hermetically sealed, water proof, light proof package. Every opto 22 solidstate relay is subjected to full load test and six times the rated current surge both before and after encapsulation. Latchingnonlatching relay driver circuit with darlington optocoupler. As a fan of vox amplifiers from both the english j.
An optoisolator is an electronic component that transfers electrical signals between two. But the circuit shown in figure 2 is completely isolated from. Vishays lh1518 solid state relays ssrs are miniature, optically coupled relays with highvoltage mosfet outputs capable of switching ac or dc loads from as little as nanovolts to hundreds of volts. The vox1 kit has 80ma of output that operates a relay, light, motor etc. The first posted circuit could be further simplified by changing the 100k and the 33k resistors to 47k. The simple application circuit of figure 2 can be used with digital inputoutput signals only but, in practice, this basic circuit can easily be modified for use with analog inputoutput signals, as shown later in this article. This will isolate between input and output section for safety. Vox korg cambridge 30 and cambridge 30 twin modifications by will page, 2006 background. The vox cambridge 15 is a small hybrid 1x8 15 watt combo amp that was introduced by vox in 1999. What is the difference between a relay and an optocoupler. The wellestablished relaydriving circuit uses an optocoupler to isolate the grounds and noise coupling between the lowvoltage digitalcontrol signal circuit.
With power indicator,8way road has a status indicator. Amplifier shortoverload protection circuit 2 ideas. Electrical engineering stack exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. The following article explains 2 simple amplifier short circuit or overload protection circuits for safeguarding amplifiers from burning why we need a short circuit protection. The diagram of figure 2 shows a bidirectional opto coupler input interface circuit.
These modules can be used either with two channels or for reliably switching higher loads e. When the bulb fails in the cambridge 30 opto coupler, the amp loses 90% of its output power and is stuck in the quiet side of the tremolo cycle. Circuit options explore issues, solutions for relay drivers. These simple optocoupler relay driver circuits can be used in variety of electronic projects. Ive gotten an older solid state vox pathfinder 15 that needs a little tlc. You mean like its alternative, or like the next in series device.
The mosfet switches are ideal for small signal switching, primarily suited for dc or audio frequency applications. He basically connected an opto coupler between a micro and a relay, done. Jan 17, 2020 the following post describes how to drive a relay by using an isolated method, or through an opto coupler device. Sep 15, 2019 this is the linear opto isolator circuits that use a few parts and cheap. Aug 04, 2019 the given amplifier shortoverload protection circuit diagram, shows an inexpensive design using just a single transistor for implementing the intended feature.
Vintage vox cambridge 15 v9159 tube combo amp 1954 music. I can get the lt9914 but by all accounts this seems to be unreliable i have also tried to locate the suggested replacement vlt5c3 but cannot find reference to it from any of my usual suppliers farnell, rs etc. Controlling relay with optocoupler, resistor confusion. The design of this circuit is based around an integrated circuit that ensures very high sensitivity. It can be controlled directly by microcontroller raspberry pi, arduino, 8051, avr, pic, dsp, arm, arm, msp430 ttl logic. Each relay has normally open and normally closed contact. Here is the list of various types of relays, their working and applications. Your external 12 volt supply connects to the voc pin on the 4pin header.
Circuit analysis with leds, bjts, relays, opto couplers. Simple voxaudio activated relay circuit for 2 meter digi modes. Printed circuit series ssrs mount on circuit boards and control up to 4 amps. The circuit was designed to interface a mains driven thryristor motor controller to low voltage analogue circuitry. The question was asked by one of the interested members of this blog, miss vineetha. The in1 and in2 pins connect to your arduino, just as i wrote before. The below shows the control logic circuit used in the optocoupled relay board. This configuration will detect dc signals and also allows you to control ac powered equipment. With r1 and r2 at those values, the opto transistor will always be switched on. Replacing the optocoupler in a ss vox pathfinder 15 the.
The trem is very weak and its a little noisy, so as a first step i was going to replace the optocoupler. An optocoupled solidstate relay contains a photodiode opto isolator which drives a power. The vox 1 kit has 80ma of output that operates a relay, light, motor etc. So, if the gain of the relay driver is 200 and, the gain of the transistor within the opto coupler is 10, the total gain is now 2,000. Geri 12v 4channel relay module with optocoupler hl level. Ive gotten the part and just want to make sure ive got orientation correct in my head before proceeding with removing the older part and installing the newer part. Input and output end suppressors, integrated operating display and a 3. The vox showroom vox cambridge 30 amplifier a look. This means that you require much less forward led current from the controller io port pin to turn on the relay. These relays are also called as impulse relay, stay relays or keep relays as they continue the process what they are doing in the last state when the power is switched off. Sensor optocoupler relay or optocoupler plc motor contactor motor r900 series the fastest optocoupler in the market spacing. Vox cambridge 15 and cambridge 30 reliability upgrades, mods. How to make an 8 channel relay driver board optically isolated. This double testing of every part before it leaves the factory means you can rely on opto 22 solidstate relays.