DC Blocker – Power DC Offset Compensation – 3A, 7A, 15A


Universal DC Blocker/ Filter, DC Offset Compensation Circuit

  • Deep suppression of Direct Current component
  • High reliability
  • Extended lifetime
SKU: N/A Categories: ,


DC Blocker / filter prevents direct current and very low frequency currents from flowing into AC power loads.

Medium to high power transformers can be very sensitive to the DC component in the power feed, even to very small amounts of it – producing hum and buzz constantly, or depending of the time of day. Sometimes the nuisances caused by the DC Offset in power lines may come and go in a manner of slow waves, that makes this effect only more noticeable. Audio power amplifiers are the first to be offended by the DC and very low frequencies in the power line. Less power hungry audio gear may also be subject to an increased noise due to the DC Offset.

In an ideal World the sinusoidal voltage in power outlets (50Hz or 60Hz) must be 100% symmetrical. Such symmetry guarantees that there is no DC component in the power supplied to the equipment. In the real life there are multiple factors that can and do distort that symmetry, effectively introducing a DC voltage offset. Culprits are countless: Any (cheap) appliance that utilizes diodes to attenuate its power, improperly loaded AC motors, industrial apparatus fed from the same power station, not-so-well designed SMPS (switching mode power supplies) which can be found in every computer and the bulk of home appliances. Even turning some heavier loads on and off often causes intermittent imbalance in the power feed, hence the very low frequency component.

We’ve seen DC offsets as low as tens of millivolts already impacting performance of big transformers. There were cases where more than a volt of a DC component was measured on a domestic power line.

DC Blocker / filter can be modelled as capacitor that passes AC currents and blocks DC completely. Such a capacitor needed for practical currents and voltages would be impractically big and expensive. This product provides properly sized capacitor banks with the schematic around it necessary to prevent any damage that may be caused to the smaller capacitors in corner cases. As a result we can offer you a very much ideal DC Blocker at a reasonable cost.

Professional design
This is a very simple design, yet there are small things that add big to its efficiency.

High current Schottky diodes provide for the minimal loss and dissipation.

Overcharge/ Overvoltage protection circuitry – unlike a plethora of competitive implementations in variety of DC blockers, our design prevents electrolytic capacitors from early ageing and possible failures due to overvoltage.

Heavily Overrated Capacitor Banks are leaving ample headroom for capacitors maximum ripple current, therefore guaranteeing virtually unlimited capacitors lifetime in the DC Blocker application.

Additional information

Weight 0.3 kg
Dimensions 1 × 1 × 1 cm

3A, 7A, 15A


There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

You may also like…

Your cart is currently empty.