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To complement the 60 Watt MosFet Audio Amplifier a High Quality Preamplifier design was necessary. A discrete components topology, using + and - 24V supply rails was chosen, keeping the transistor count to the minimum, but still allowing low noise, very low distortion and high input overload margin. Obviously, the modules forming this preamplifier can be used in different combinations and drive different power amplifiers, provided the following stages present a reasonably high input impedance (i.e. higher than 10KOhm).... [read more]

Due to the low current drawing, the circuit can be supplied from 230Vac mains without a transformer. Supply voltage is reduced to 12Vdc by means of C1 reactance, a two diode rectifier cell D1 & D2 and Zener diode D3. IC1A, IC1B, R2, R3 and C3 form a reliable bounce-free toggle switch operated by P1. R4 and C4, wired to pin #6 of IC1B reset the circuit (lamp off) when power supply is applied. IC1C and IC1D wired in parallel act as a buffer, driving the Gate of the Triac through R5.... [read more]

The simple conjuring trick is intended to provide some enjoyment for the beginner in electronics or conjuring, and should take only an hour or two to build.... [read more]

This is a medium range transmitter circuit diagram. This is also improved by changing the values of the resistor.... [read more]

It is a simple circuit regulated power supply, based on the known LM 723, that drive a transistor Q1 [2N3055]. The regulation of voltage, of expense becomes with potentiometer R1 from 0v-30v DC roughly. In order to we achieve 30 V, will should the transformer of supply TR1, it gives all the current that it asks the load, differently the output voltage it will be found in the levels of 26 V roughly. Essential is the use of a good heatsink for transistor Q1, as well as good quality of potentiometer in the place of R1.... [read more]

Feeling chirpy? Attract new friends with this modified hartley oscillator. You could also use it as a replacement doorbell.... [read more]