In most lab experiments and so many electronics projects as well as hobby work we need a variable voltage source. Now, most sources like the AC programmable or non programmable power source or a variac are simply too expensive. So what's the next best practical choice? An SCR Dimmer. This can vary the output voltage from zero to full 100% by the turn of a control knob. The only catch one has to keep in mind is that the output upon dimming does not remain a pure sine wave but is interrupted at a point on the sine wave whose position depends on the dimming level. Please refer to Fig.1 below for clarity:
Image credit: electronics.stackexchange.com
Depending on how much the triggering point is away from the zero crossing point of the input AC waveform we get a delay in the output waveform start and this way the output power is easily controlled. Most electronic circuits can also be tested using the output peak point as the output voltage level after measuring with an RMS multimeter. For a more accurate measurement of course one should use a variac or a pure sine wave voltage source.
We would like to recommend the Xcluma Dimmer shown above. The features of this model are given below:
NOTE: Load must be connected before the voltage is adjusted .
Thyristors are mainly used for resistive loads (heating filament incandescent lamps, etc.). Most single-phase AC motors are also Supported, but all motors are not guaranteed. Other types of loads are subject to buyer's confirmation.
The fuse is not a Permanent Solution. It has a response time. If the current is too large, the module may be burned apart from the fuse. It is 4000watt and work well but recommended for 2000watt load if used for longer time.
Voltage Regulation: AC 0-220V Size: L85mm x W60mm x H40mm rotation hole 6mm SCR Model: BT-800B
Voltage: AC 0-220V Maximum power: 4000W