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This circuit uses a CA3420 BiMOS op amp to form a picoammeter with 4 ranges. The exceptionally low input current (typically 0.2pA) makes the CA3420 highly suited for use in a picoammeter circuit. Input transient protection is provided by the 1 megohm resistor in series with the input.... [read more]

This is the schematic for an FM transmitter with 3 to 3.5 W output power that can be used between 90 and 110 MHz. Although the stability isn't so bad, a PLL can be used on this circuit.... [read more]

This timer will provide a sequence of up to ten separate events. The length of each event is set independently. And the sequence will run a fixed number of times - or repeat continuosly. The individual events within the sequence - can be made to repeat and/or overlap. The accompanying Support Material includes a detailed description of how the Cmos 4017 works.... [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]

Most cards of sound in computer, are deprived stereo input for microphone, on the contrary have stereo input for high level [ Line ]. The circuit uses the input Line of card of sound, in order to we place a two mono stereo microphone, in the input of card of sound. Simultaneously he is more functionnal, after we have the possibility of regulating the gain of stage of microphone and regulating the final level of sound externally and independent for each channel of microphone.... [read more]

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]