Pure A class is the most simple topology for designing an amplifier! The tube or the power transistor is loaded directly by the speaker (often thru a transformer, fro impedance matching!), and is biaised at the current necessary for full modulation (that means a maximum power dissipation for no input signal).

The guitar input stage is a class A amplifier with adjustable bias. A 2N3906 PNP tranistor is used for a low noise design on this stage. The output of the preamp stage is sent to three places: the output mixer amp, the reverb driver amp, and the input clipping detector. The reverb driver amp consists of a phase inverting push-pull circuit made from dual sections of a 5532 high quality audio op-amp. This provides a voltage swing of approximate twice the supply voltage to the reverb impedance matching transformer, allowing higher power transfer. The 100 ohm resistor is critical for insuring a clean drive signal, without it, the op-amps can saturate when driving the transformer, producing unwanted distortion.

This is my second-generation guitar reverb circuit. The fidelity is much improved over the earlier design, it is suitable for use as a front-end to a guitar amplifier. This circuit features clipping indicators on the preamp and reverb recovery stages, allowing for the optimal gain settings. The guitar input stage is a class A amplifier with adjustable bias. A 2N3906 PNP tranistor is used for a low noise design on this stage. The output of the preamp stage is sent to three places: the output mixer amp, the reverb driver amp, and the input clipping detector. The reverb driver amp consists of a phase inverting push-pull circuit made from dual sections of a 5532 high quality audio op-amp. This provides a voltage swing of approximate twice the supply voltage to the reverb impedance matching transformer, allowing higher power transfer.

The source connection is tapped into the tuning coil low down, as a means of impedance matching with the headphones and acts as the anode, while the drain connects with your headphones as the cathode, to complete the detector part of the circuit. According to the experts on the net, much success has been enjoyed by one and all, and there's a lot of chatter about this most recent innovation in the realm of simple AM receivers (292 posts so far, to the 'Rap'n'tap' chatroom of the American Crystal Set Society alone!- www.midnightscience.com). One of the most curious aspects of this little beauty is that the antenna/ground system I employ basically entails a 'short' antenna, and a water pipe ground. Ideally, short antenna wires work best near the top of the tuning coil, but in this case, the best position seems to be right at the bottom tap! Normally, this would send all my weak locals into a spin, and shift the whole band up towards the top end of the tuning cap's range.

This is a simple little 800 MHz band cellular phone jammer which can be easily built from commonly available parts. Most homebrew cellular phone jammers are based around a sweeping RF oscillator which, while more "jamming" efficient, can be quite difficult for the beginner to construct without access to expensive RF test equipment. This project can also be used to help take the load off certain people who receive 15 million emails a day from strangers asking them how to build their own cellular phone jammers. This cellular jammer is based around a common 45 MHz clock oscillator driving the Local Oscillator (LO) port on a Mini-Circuits ADE-1ASK mixer. This LO signal also passes through a simple impedance matching network to transform the high impedance of the clock oscillator down to the mixer port's 50 ohm impedance.

This will probably be one of the last transmitters for the 88MHz to 108MHz band. This particular TX is of special interest to those wishing to build low power Power Amplifiers for the VHF bands since it used impedance matching, power amplifier and antenna filtering, all of which should be used by radio constructors, whether it be for amateur radio or any other form of radio. The features of this project are: Higher output power - 150mW min (at 9v) and 300mW+ (at 12.5v). Very pure output signal due to carefull design and filtering. VARICAP modulation - possiblity to add a synthesiser. Single sided Printed Circuit Board, only 40mm x 72mm. Covers the domestic FM band - 88MHz to 108MHz. Easy to build, but coil winding experience IS required.

This circuit uses buffer stages to prevent channel crosstalk back through the mixer resistor network. The potentiometers used for each stage allow for convenient signal strength adjustment, while maintaining input impedance matching at the 600-0 audio standard.

This amplifier employs a cascaded op amp integrator and transistor buffer, Q1, to drive the gain control element. Except for a simple modification, the HA-5190/5195 stage is connected as a conventional noninverting op amp, and includes input and output impedance matching resistors R1 and R4, respectively, series stabilization resistor RZ, and power supply bypass capacitors C1 and C2. The circuit differs from standard designs in that the gain control network includes a photoresistor, part of OCl. The optocoupler/isolator OC1 contains two matched photoresistors, both activated by a common LED.

Place the transciever and the chip antenna very close, then there is no need for a 50 ohm transmission line right If so, can I somehow merge those two matching circuits into one and thus reducing component count

183. 6MHz SAW filter in a CDMA application. The SAW filter S-parameter is used to simulate the interface with the mixer. A worked example is provided with a SAWTEK 855893 SAW filter. An optimum impedance matching circuit between the MAX2338 mixer differential IF ports and a 183. 6MHz CDMA IF SAW filter is presented in this application note. A practi

Here is a simple IR headphone circuit that is suitable for listening to TV or radio with out disturbing others. For beginners the IR headset is a better option than FM head sets because they often produce desirable sound quality with out tuning as well as difficult impedance matching that is often done in radio circuits which is difficult for begi

amplifier input and output impedance, load and source resistance are strongly mutually dependent in the CC circuit. That`s a reason, why "impedance matching" doesn`t achieve results representative for the circuit operation. Analyzing the circuit as CB with virtual ground, as suggested by LvW, gives a better decoupling of both amplifier ports. Impe

An electronic musical keyboard as a source of variable-frequency AC voltage signals. You need not purchase an expensive keyboard for this - but one with at least a few dozen "voice" selections (piano, flute, harp, etc. ) would be good. The "mono" plug will be plugged into the headphone jack of the musical keyboard, so get a plug that`s the correct size for the keyboard. The "impedance matching transformer"

Buffering for the zener is provided by the impedance matching and current amplifying characteristics of the emitter follower and draw less current from it. To..