Isolators/Solid State Relays
Common
- What is a photocoupler?
- Why is a photocoupler necessary?
- What types of photocouplers are available?
- What is the internal structure of a photocoupler?
- How many volts can be applied to the input side LED?
- Is it possible to use a photocoupler in such a way that for items such as the LED current, output current, and output voltage, the value specified for the absolute maximum rating is exceeded for a short time?
- What are the parameters specific to photocoupler and photorelay optical isolation devices, transfer ratio (CTR), trigger LED current, and threshold input current?
- How are the current transfer ratio (CTR), trigger LED current, and threshold input current measured?
- For a photocoupler and photorelay incorporating a LED device, in designing equipment, which should be considered: LED life or photodetector life?
- A photocoupler is an isolation device. What is dielectric strength, which indicates its insulation capability?
- What is the difference between a photocoupler and a photorelay?
- What are the safety standards required for photocouplers?
- What are required by safety standards applicable to photocouplers? How are they specified in products?
- How can I find safety standard authentication information about photocouplers?
Transistor coupler
- What is the current transfer ratio?
- What is the CTR classification by rank?
- Why are there two current transfer ratios: CTR and CTR (Saturation)?
- What is the difference between a dark current and OFF-state collector current?
- Why is VECO very low (0.3V) for Darlington transistors such as TLP187 and TLP387? What precautions should be taken when using such transistors?
- In designing a circuit using a transistor coupler, how should the current transfer ratio be reflected?
- How should a circuit driving the LED of a transistor coupler be selected?
- In a circuit using a transistor coupler, how should load resistance be selected?
- How many volts are minimally required for transistor couplers to operate?
- How many milliamps are minimally required for transistor couplers to operate?
- Up to what frequency can transistor couplers transmit signals?
- For a transistor coupler with the base terminal, if not using the base terminal, is it OK to keep the base terminal open and do nothing?
- For IC couplers, there is a requirement related to common-mode transient immunity. However, for transistor couplers, such a requirement does not exist. Why?
IC coupler
- What is the threshold input current?
- In designing a circuit using an IC coupler, how should the threshold input current be reflected?
- How should a circuit driving the LED at the input side of an IC coupler be selected?
- In a circuit using a high-speed IC coupler, how should output pull-up resistance be selected?
- For example, for 1Mbps-type IC couplers such as TLP109 and TLP759 to operate, how many volts are minimally required?
- For IC couplers, some products are defined with a threshold input current, and others are defined with a current transfer ratio. What is the difference between them?
- Is a bypass capacitor required between the VCC and GND terminals?
- How should a frequency for signals that can be transmitted by a high-speed IC coupler be estimated?
- What is the UVLO function?
- Is there any problem with waveforms with input signals rising or falling gently?
- What is the difference between the open collector output type and the totempole output type? Also, what precautions should be taken for use?
- What is the voltage range in which IC couplers can operate?
- What is common-mode transient immunity? Why is this required for IC couplers?
Standard Digital Isolators
Photorelay
- How can I find the resistance values when the photorelay is OFF and when it is ON?
- Up to what level of voltage can be used at the switch section of a photorelay?
- How much input current should be passed for switch operation?
- Up to what level of current can be used at the switch section of a photorelay? Also, for a pulsed current or AC current, what happens?
- For signals to be switched, up to what frequency can be used?
- How long does it take from when an input signal enters until the switch changes?
- Can photorelays be used by series connections or parallel connections? If yes, what points require attention?
- What is the CR product of the photorelay?
- Can photorelays be replaced with and used in the same way as mechanical relays? What is the difference, if any?
- What are Form A contacts and Form B contacts in a photorelay? Also, what are A, B, and C connections? What is the difference?
Triac coupler
- For what purposes are triac couplers used?
- What precautions should be taken when replacing mechanical relays with triac couplers?
- What are the differences among triac couplers, SSR (solid state relays), and photorelays?
- What is the difference between zero-cross triac couplers and non-zero-cross triac couplers? How should they be used properly?
- What precautions should be taken when performing phase control with triac couplers?
- For triac couplers, how should a VDRM (400V, 600V, 800V) be selected?
- How much input current should be set for turning the triac ON/OFF?
- What precautions should be taken when using triac couplers for a long time?
- How should values be selected for the constants for the snubber circuit connected to the triac?
- When using a triac coupler to drive the main triac, how should the current limiting resistor RT directly connected to the triac be determined?
- Can high-frequency signals be switched ON/OFF with a triac coupler?
- When controlling a load with a triac coupler, can a load be controlled even if using a rectangular wave power supply at the load side instead of a sinusoidal wave (AC) power supply?
Fiber-Coupler(TOSLINK™)
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