For a wireless inductive charger, I understand the basic operating principle. I have a question regarding the operation of such chargers when no "load" is "connected". How do they detect the presence of a "load" so that the transmitter doesn't constantly have to transmit?
Electronic – How do inductive chargers detect a load
chargerinductive
Related Solutions
LEDs are a nonlinear load and probably these lamps will not have a power factor correction converter. This means that the current will not be sinusoidal therefore you will have some reactive power flowing. There may be a PFC choke before the rectifier bridge.
If you want to measure the power factor and harmonic content just take a scope with voltage and current probes and measure line voltage and line current.
PS. This it how you distinguish China Export mark from European CE:
I'm assuming that you mean a battery charger, and a lead-acid charger in particular. A typical scenario is that the charger applies a constant current to the battery until the voltage rises to the desired level, maybe 14.4V for a 12V battery. The charger then switches to constant-voltage charging at this voltage until the current falls to some small value. At that point the red light goes out, the green light goes on, and the charger switches to a lower "float" voltage.
The circuitry involved is generally much more than a transistor. To do this right you need a good voltage reference, a circuit that converts the charging current to a voltage, some comparators, and some flip-flops to keep track of the current charging mode.
Related Topic
- Electronic – Is the efficiency of (Qi) wireless charging affected by a metal surface
- Electrical – Effects of rapidly pulsing DC inductive load on solid state relays
- Electronic – Eleminating radiation from chargers
- Electronic – What’s causing the audible 7/8th rhythm in Qi chargers
- Electronic – Determining direction from an inductive joystick
Best Answer
Have you read this article ?
The transmitter transmits bursts and detects the resulting current flow in the transmit coil. Depending on the value/shape of that current the transmitter can detect if there is a load present, nothing present or a foreign object present.
When a load is present the voltage and current in the transmit can be influenced (modulated) by the load. That way communication can take place. It is almost identical to how RFID and NFC work.