Circuits & Schematics: power supply - 7

61. Gnat-power sawtooth oscillator works on low supply voltages
    Circuits Oscillators TS12011 TS12012
    .. circuit, drawing less than 3.2 uA and working at under 1 V, is a useful building block that fits the bill for extremely low-power consumption and operation to low supply voltages. It could be used as the basis for a PWM control loop, a ...
    Dec 19, 2013

62. Power resistor varies in value
    Bogdan Raducanu
    Circuits Measurement Supply
    .. power supplies or discharging batteries usually requires a constant-current load. Sometimes, however, you must study ...
    .. with low-cost components. Depending on the op amp’s input range, the circuit requires an external dual power supply. Figure 2 shows a prototype of the tested and built circuit using a potentiometer for changing the equivalent ...
    Jul 16, 2020

63. Flash an LED from ac-mains power
    T A Babu
    Circuits Supply Light Fairchild LM317
    .. Babu EDN LED technology is opening the door to a variety of high-power-illumination applications. The circuit in Figure 1 can let you know when ac power is available. To drive a ...
    .. the total design. You can also simplify the circuit to run on dc power, which lets you use it from automotive batteries to supply light at night. Figure 1. This circuit uses a simple DIAC relaxation oscillator, which activates a ...
    Jul 26, 2020
64. Single-Supply Circuit Measures -48 V High-Side Current
    Circuits Supply AD629 AD8603
    .. operational amplifier, both from Analog Devices, to measure current at 48 to 60 V and operates from a single positive-power supply. Figure 1 shows how the AD629 and AD8603 measure current in the presence of a 48 V common-mode voltage. ...
    .. 60V. Measuring its current draw typically requires components that operate on 15V dual supplies. Eliminating the negative supply would reduce system complexity and cost. This Design Idea uses an AD629 difference amplifier and an AD8603 ...
    Apr 9, 2008
65. IC Performs Delayed System Reset Upon Power-Up
    Circuits Microcontrollers Usage Theory Maxim MAX6805
    .. for a certain period of time before you can apply the reset, or active low. The circuit in Figure 1 proves useful during power-up when there is no need to press the reset button once the device powers up, because reset occurs ...
    .. the transistor discharges C 2 . Once this action happens, Q 1 turns off. R 1 charges up the negative side of C 1 to the supply voltage, V DD . Because the positive side of capacitor C 1 cannot change instantly, it appears to be charged ...
    Apr 11, 2008
66. Mains sockets switched automatically by a Control Socket Up to 1000W switched power
    Circuits Domestic Supply
    .. appliances will be automatically switched off. A further application is the control of a High Fidelity chain, plugging the Power Amplifier in the Control Socket and - for example - CD Player, Tape Recorder, and Tuner in the Switched ...
    .. if the control appliance is on or off. This could also happen when devices connected to the mains by means of plug-in power supply adapters are used as control appliances, due to their lack of a mains switch. In spite of this restriction, ...
    Jul 20, 2009
67. Supply Voltage Indicator
    Circuits Supply
    .. Adzic - Serbia Montenegro Description A novel supply voltage monitor which uses a LED to show the status of a power supply. Notes This simple and slightly odd circuit can clearly show the level of the supply voltage (in a ...
    Dec 15, 2009
68. Power Fail Alert
    Circuits Supply LM317
    .. R1, trickle current being several milliamps. Q2, Q3, R5 and BZ1 ( a piezo sounder) form a solid state alarm. As long as the power is on, D3 and R4 positively bias Q2 into saturation. Q2 collector will be close to zero, and hence Q3 and the ...
    .. Collinson Description In this circuit an electricity supply (domestic or industrial) is continually monitored. Should the supply be interrupted then an alarm will sound ...
    Sep 27, 2010
69. 1.3 Volt Power Source
    Circuits Supply
    .. Collinson Description This is a replacement power source for 1.3V mercury cells or other small batteries. It has many uses and I use this circuit in my computer ...
    .. Notes This circuit takes it power from a PC. The power connectors have colour coded wiring, red and black are the 5V supply, black and yellow are the 12V supply. These are extremely high current so absolute care must be taken to ...
    Oct 4, 2010
70. Single-/Dual-Supply Precision Analog Limiter Handles Wideband Signals
    Alex Rysin
    Circuits Analogue Design Linear Technology LT1810
    .. in Figure 1 precisely limits the wideband input signal Vi at the V REF level and can be used with both single and dual power supplies. Figure 1. This analog circuit, based on the LT1810 op amp, precisely limits input signal V I at ...
    Aug 17, 2017

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