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Symmetrical Class A Preamplifier

A very simple but very good amplifier unit, with low distortion. A similar modification was used as a preamplifier HAFLER. The quality however of the reproduced sound in all the symmetrical amplifiers regardless of the cost of the necessary materials, transistors, capacitor and resistors.... [read more]

Power Supply +50V 3A stabilized and regulated

Many times we needed a stabilized, together regulated power supply and high relatively output voltage. These specifications him it cover our circuit. It 's a circuit that can give in his exit + 40V until + 60V 3A, with simultaneous stabilization.... [read more]

Controlling a relay with a digital logic level.

The schematic illustrates 4 methods of controlling a relay with a digital logic signal.... [read more]

Audio Peak Indicator

A peak level indicator when a signal exceeds a certain maximum value. It can be quite useful, for instance, with tape recorders, mixing consoles etc. One of the most important requirements of a peak level indicator is that it should respond to very short signals.... [read more]

VU Meter 4

The circuit is placed parallel with the exit of power amplifier and us gives the level of signal ,from output. Changing resistance R1, in the input circuit, we adapt the indication of power, in the resistance of loudspeaker, that we use.... [read more]

Repeating Timer No5

This circuit is a temperature controlled version of Repeating Timer No.3 . The light dependent resistor has been replaced by a temperature dependent resistor or thermistor. And a small preset potentiometer lets you choose the temperature above which the timer will operate.... [read more]