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