This circuit operates from a 16- to 50-V supply. Adding the buffer circuit (within the dashed lines) offe..
A charge pump is a simple means of generating a low-power voltage supply of opposite polarity from the main supply. The 74Cl4 IC is a self-oscillating driver for the MOSFET power switch. It produces a pulse width of 6.5 p,s at a repetition frequency of 100 kHz. When the MOSFET device is off, capacitor C is charged to the positive supply. When the power through the MOSFET switches on, C delivers a negative voltage through the series diode to the output. ..
A MOSFET is used as a wideband buffer amplifier. T1 is wound on a toroid of approximately /f diameter, with material suitable for frequency (usually 1- to 20-MHz range). The turns ratio should be about 4:1 depending on load impedance. Typically, at 4 MHz, there are 18 turns on the primary, ..
This circuit is an improved front end for upgrading a transistor AM receiver. This front end is useful ..
Two complementary MOSFETs are used to deliver 20 W into 8 . A TL071 op amp is used as an input amplifier. The MOSFETs should be heatsinked with a heatsink of better than 5C/W capability...
Requiring only 10uA of quiescent current, the circuit of (Fig. 62-1 (a)) produces only 0.1ohm ON-resis-tance...
Because the combination of one MOSFET and negative VGS would allow current flow in the off state (because of forward bias on the MOSFET`s internal parasitic diode), the circuit in Figure 1 connects the two MOSFETs source to source. Their internal diodes then oppose each other, which blocks unwanted current flow to either polarity in the off state...
Sensitive systems, such as those in aircraft, must withstand fault conditions, thereby avoiding component and system damage, because a sensor failure could cause a catastrophic event to occur. A channel protector, comprising two n-channel MOSFETs connected in series with a p-channel MOSFET, can protect sensitive components from voltage transients in the signal path, whether or not the power supplies are present (Figure 1)...
This paper details the design, development, assembly and performance of a low cost, high efficiency, 400Watt, 13.56MHz RF power amplifier (PA) operated from a 100VDC supply and with an efficiency of 75%. The PA is built around a Symmetric Pair of low cost RF power MOSFETs from Advanced Power Technology (APT). The transistors are from a new generation of high quality, commercial, HF/VHF, silicon, 300V RF power MOSFETs in TO-247 plastic packages...
Can be directly connected to CD players, tuners and tape recorders. Simply add a 10K Log potentiometer (dual gang for stereo) and a switch to cope with the various sources you need...
This is yet another method to generate low frequency output pulses. The circuit uses an inexpensive under-voltage monitor IC and a couple of cheap MOSFETs. It could easily be modified to produce pulse frequencies from about one cycle per minute to a maximum of about 10KHz. It draws only about 1uA from a 3v battery. This circuit should not be used if frequency stability is important, since it will change as a function of supply voltage...
In many applications, it`s desirable to disable LEDs used for system verification. Many options are available for the disabling function, including manual SPST (single-pole single-throw) switches, enhancement- and depletion-mode MOSFETs, bipolar-junction transistors, and JFETs. The circuit in Figure 1 automatically disables the LEDs when a mechanical housing encloses the circuit card, thereby preventing you from accidentally leaving the LEDs on to waste power...
Here i propose a project of an AB class power amplifier, at its simplest, assembled with common compoments (not very expensive), based on traditional diagrams : a symmetrical differential input stage, a cascode stage driver and a MOSFET output stage. The printed circuit board is very compact , and is composed of two subsets : the command stage and the output stage. All resistors are 1/4 watt 1 % metal film (except if otherwise stated). Constant current sources of +/- 1 mA.....
The circuit in Figure 1 uses a MAX234 RS-232C driver, with the addition of a few capacitors and diodes, as a level translator. The circuit allows TTL-level signals to drive four power MOSFETs. The MAX234 is a line-driver chip that translates TTL-level signals to the RS-232C levels that serial communications require...
This circuit speaks for itself. When the phone line is okay, Q1 acts as a short with a very high ohms value via R1, R2, and R3 for a total of about 66 MegOhm so very high. When the phone line is cut (open), it activates the MosFet (Q3) via transistor Q2 to drive the load. Substitutes are fine, none of the components are critical. The `Red` and `Green` wires of a telephone wire are *NOT* the positive and negative. They are the TIP and RING wires. So, don`t get confused why.....
A power MOSFET is biased using a pot (needed to correct for different device characteristics) so that the voltage at the drain is about 1/2 the supply voltage. Current is limited using a constant current source, and this needs to be set to provide a current that is higher than the maximum peak current to the speaker. Since the amp is not DC coupled, an output capacitor is needed to keep the DC out of the loudspeakers. An input cap is also needed to stop the source (the.....
This same circuit was also very successfully used as a current source to supply low voltage control circuitry from the same drooper. A toroidal inductor was used with the load connected in series with ot, flywheel diode connected so that drive and flywheel current both flowed through the load. The load voltage was regulated with a zener diode. It operates by PWM - well, actually by PFM - Pulse Frequency Modulation. At power up, C1 charges up via D1 and R1. R2 will conduct,.....
This headphone buffer is based on Greg Szekeres' MOSFET Headphone Driver. It is a robust and reliable zero feedback, class A circuit. [Editor: And like the Szekeres MOSFET amp, this amp has unity voltage gain. Therefore, the audio source must supply adequate voltage to drive headphones.] The power supply is choke regulated. The circuit is configured for low impedance headphones like my 32-ohm Grado SR60s. Greg's circuit was designed to be driven from the output of a.....
Can be directly connected to CD players, tuners and tape recorders. Simply add a 10K Log potentiometer (dual gang for stereo) and a switch to cope with the various sources you need. A correct grounding is very important to eliminate hum and ground loops. Connect in the same point the ground sides of R1, R4, R9, C3 to C8. Connect C11 at output ground. Then connect separately the input and output grounds at power supply ground...
A while ago I got an email asking for the schematic of a circuit to detect cut phone lines. It didn`t take me long to find this circuit in Electronics Now. When the circuit detects that a phone line has been cut, it activates a MOSFET which can be used to drive a relay, motor, etc. It can also be connected to a security system. # The "Load" can be a relay, lamp, motor, etc. The circuit can also be connected to a security system to sound an alarm in case the phone line is.....
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