BT 6.7 0 Td <20> Tj 9.1 0 Td <6D> Tj This experiment allows us to analyse the temperature increase of an 7805 linear voltage regulator as we increased the current demands on the circuit. ET 9.1 0 Td <65> Tj 9.7 0 Td <7369> Tj 49.6 586.8 Td /F2 11 Tf <61> Tj q 0 0 0.50196 rg q 0 0 0 rg 6.2 0 Td <62> Tj ET 6 0 Td <65> Tj 5.4 0 Td <75> Tj q 0 0 0.50196 rg 6.1 0 Td <7874> Tj 4.1 0 Td <74> Tj 6.7 0 Td <20> Tj 6.7 0 Td <20> Tj 6.1 0 Td <72> Tj 3.1 0 Td <6F> Tj 6.4 0 Td <20> Tj /Im3 Do Q 6.2 0 Td <20> Tj 3.1 0 Td <68> Tj BT 3.6 0 Td <61> Tj 3.1 0 Td <6F> Tj 49.6 509.3 Td /F3 11 Tf <61> Tj 6.1 0 Td <6E> Tj 6.1 0 Td <6D> Tj 7.1 0 Td <20> Tj 4.9 0 Td <69> Tj 9.8 0 Td <65> Tj 6.2 0 Td <6E> Tj Q 6.1 0 Td <63> Tj 6.1 0 Td <67> Tj 4 0 Td <69> Tj 3.3 0 Td <35> Tj 3.2 0 Td <20> Tj ET 11.8 0 Td <20> Tj 5.8 0 Td <20> Tj 6.2 0 Td <6E> Tj 9.8 0 Td <61> Tj 6.1 0 Td <6E> Tj 6.2 0 Td <65> Tj 9.8 0 Td <6F> Tj ET 6.1 0 Td <64> Tj Hook up wire, cable ties and 3mm mounting hardware is also required. A dummy load is essential for testing amplifiers, and although there is really very little involved, setting one up properly (and cheaply) can become irksome. 7.9 0 Td <68> Tj BT ET 9.2 0 Td <73> Tj 3 0 Td <69> Tj 3.2 0 Td <73> Tj 6.1 0 Td <6F> Tj 6.1 0 Td <6E> Tj This test can easily be conducted at various levels and with it, you can reproduce and verify the claims made in datasheets. 7.3 0 Td <61> Tj 6.2 0 Td <72> Tj 6.2 0 Td <61> Tj 3.1 0 Td <6A> Tj 3 0 Td <35> Tj Solder the wires directly to the PCB noting that the first pin of the fine adjustment potentiometer (10K) is not used. q 0 0 0 rg 7.3 0 Td <6D> Tj 6.1 0 Td <67> Tj ET 5.6 0 Td <77> Tj BT 11 0 Td <7465> Tj 5.6 0 Td <6A> Tj 6.1 0 Td <61> Tj 6.4 0 Td <63> Tj 6.4 0 Td <696E> Tj 6.1 0 Td <65> Tj 3.6 0 Td <67> Tj 6.1 0 Td <68> Tj 5.8 0 Td <73> Tj You can use this dummy load to simulate the load on the power supply circuit under different load conditions, to monitor the temperature curve in relation to load. 6.1 0 Td <74> Tj 179.8 283.4 Td /F3 11 Tf <2C> Tj q 0 0 0 rg 518.5 333 0.1 213.4 re f* q 0.13725 0 0.86274 rg 49.6 120.5 Td /F3 11 Tf <64> Tj 6.1 0 Td <74> Tj We are using a Uni-T UT658 USB tester. This constant resistance dummy load has not yet been tested in the real world. 6.1 0 Td <7365> Tj 6.1 0 Td <6C69> Tj 3.3 0 Td <67> Tj 9.7 0 Td <7469> Tj 3.8 0 Td <7261> Tj 7.9 0 Td <7374> Tj 3.2 0 Td <74> Tj 3.6 0 Td <65> Tj 6.2 0 Td <61> Tj 2.4 0 Td <75> Tj 6.1 0 Td <64> Tj 6 0 Td <6E> Tj 8 0 Td <6F> Tj 6.7 0 Td <64> Tj 3.4 0 Td <4C> Tj 22.7 0 Td <44> Tj What is the RMA? BT 6.2 0 Td <73> Tj ET ET To connect the LED from the front panel to the PCB we made a short lead with two 2-pin header sockets. 6.2 0 Td <73> Tj 5.6 0 Td <74> Tj 8.4 0 Td <6D7920> Tj 9.7 0 Td <77> Tj q 194.9 0 0 226.6 329 95 cm 3.3 0 Td <73> Tj 3.5 0 Td <68> Tj Q 6.7 0 Td <20> Tj 6.7 0 Td <65> Tj 6.1 0 Td <6C> Tj Q 3.6 0 Td <62> Tj BT 6 0 Td <70> Tj Q 0 0 0 rg To get the dual colour we simply embedded the lettering into the 3mm panel by a specific depth of 0.5mm. This test allows us to ascertain how hot the MOSFET will get while dissipating higher loads and, therefore, give us an idea of the maximum performance. 7.2 0 Td <20> Tj 5.6 0 Td <61> Tj 6.1 0 Td <6E> Tj 5.6 0 Td <20> Tj Q 6.1 0 Td <73> Tj 5.6 0 Td <20> Tj 2.7 0 Td <31> Tj 5.5 0 Td <73> Tj 5.4 0 Td <696365> Tj 6.1 0 Td <65> Tj 6.2 0 Td <61> Tj BT 9.2 0 Td <20> Tj ET 6.2 0 Td <2065> Tj When you’re done it should look something like this: Note: Use thicker wiring to reduce the resistance. 6.2 0 Td <6E> Tj 5.6 0 Td <75> Tj After opening the battery, I learned that one of the cells was quite low on electrolyte. 4.3 0 Td <7468> Tj 3 0 Td <6F> Tj 3.7 0 Td <68> Tj 6.1 0 Td <6D> Tj 7.4 0 Td <20> Tj 12.1 0 Td <20> Tj 6.7 0 Td <77> Tj Q 9.2 0 Td <69> Tj 2.5 0 Td <74> Tj 6 0 Td <6F> Tj 5.6 0 Td <20> Tj 6.1 0 Td <61> Tj q 0 0 0 rg Small increases in current can create significantly higher temperatures when the heat inside the enclosure has no way to be removed. The panel image shown above was the first attempt at the front panel. ... lutron do a dummy load box as there grafik eyes have a minimum 40w or 60 w load , just fitted 2 myself and they were about £70 each Top: Bottom. We could buy a 4 Ohm resistor, an 8 Ohm resistor and a 16 Ohm resistor and connect them individually to speaker cables and use them separately, but that would be too easy. 6.7 0 Td <6C> Tj 4.2 0 Td <20> Tj 5.5 0 Td <69> Tj q 0 0 0 rg 6.1 0 Td <67> Tj 6.1 0 Td <73> Tj 5.5 0 Td <73> Tj 6 0 Td <6E> Tj 3.1 0 Td <20> Tj BT 7.1 0 Td <20> Tj BT 5.4 0 Td <666F> Tj 3.6 0 Td <7468> Tj The voltage applied to R23 is controlled by the enable/disable switch and by the power limiting circuit. 6.1 0 Td <6C6C79> Tj 6.2 0 Td <65> Tj 2.8 0 Td <75> Tj 9.1 0 Td <7320> Tj 11 0 Td <65> Tj 6 0 Td <6E> Tj 14.3 0 Td <20> Tj 6.1 0 Td <64> Tj Practically it is a device that simulate an antenna, and permit to test transmission without radiating, absorbing the amount of power that the transceiver delivers. 6.2 0 Td <30> Tj 2.4 0 Td <6E> Tj 3.3 0 Td <7468> Tj 6 0 Td <72> Tj 2.4 0 Td <65> Tj 6.1 0 Td <6E> Tj 6.3 0 Td <63> Tj 4.9 0 Td <77> Tj To implement a variable dummy load, a variable voltage regulator LM317 connected as shown in the following diagram is used. 2.4 0 Td <7320> Tj 7 0 Td <20> Tj 5.6 0 Td <35> Tj 2.7 0 Td <32> Tj 6.1 0 Td <70> Tj 2.5 0 Td <73> Tj It was printed in two pieces both being positioned flat on the build surface. A Darlington pair is used to provide high impedance input since we want to use a low wattage potentiometer to vary the loading. 2.8 0 Td <20> Tj q 0.27843 0 0.72156 rg 6 0 Td <30> Tj 9.1 0 Td <65> Tj A load bank may be used to stabilize a power system in case of loss of load, for example, on an isolated wind or mini-hydro plant. << 6.6 0 Td <68> Tj 135.8 495.4 Td /F1 11 Tf <64> Tj 8.5 0 Td <65> Tj You then need to dial in the desired current using the current display on the multimeter or the USB tester. 14.7 0 Td <77> Tj ET 3.1 0 Td <6F> Tj 7.1 0 Td <20> Tj 4.3 0 Td <20> Tj 2.8 0 Td <62> Tj 2.7 0 Td <53> Tj 6.2 0 Td <61> Tj This, in turn, saturates the gate of the MOSFET, which allows current to flow from the MOSFETs Drain to the source. 9.1 0 Td <20> Tj 6.1 0 Td <7365> Tj 17.3 0 Td <75> Tj 3.7 0 Td <65> Tj 7.3 0 Td <20> Tj 3 0 Td <6E> Tj 3.2 0 Td <65> Tj 3 0 Td <20> Tj 5.6 0 Td <72> Tj 6.7 0 Td <20> Tj You don't need to pollute the airwaves while just tuning or testing your transmitter! 6.1 0 Td <72> Tj 4.9 0 Td <746F> Tj q 0 0 0 rg 3: Complete circuit diagram of dummy load. 4.9 0 Td <61> Tj 49.6 38.4 Td /F3 10 Tf <43> Tj 4.2 0 Td <72> Tj 3.3 0 Td <5365> Tj 2.7 0 Td <54> Tj 9.1 0 Td <20> Tj 6.1 0 Td <72> Tj 2.4 0 Td <65> Tj 7 0 Td <20> Tj 8 0 Td <20> Tj You will notice in the photo shown here that we used heatshrink on the connections and cable ties to avoid the wiring from touching the heatsink or fan. 6.1 0 Td <69> Tj 5.5 0 Td <6F> Tj 6.1 0 Td <69> Tj 2.5 0 Td <6C> Tj The circuit is essentially little more than an operational amplifier in the voltage comparator configuration, connected to a MOSFET and Shunt resistor. 49.6 468.3 Td /F3 11 Tf <6E> Tj 49.6 66.3 Td /F3 11 Tf <72> Tj 6 0 Td <2C> Tj >> 6.9 0 Td <20> Tj q 0 0 0 rg endobj 3.1 0 Td <48> Tj 6.1 0 Td <6E> Tj 6.7 0 Td <61> Tj it can handle more than 600watts (i want to use it for PA amps too) :p. Logged jjasilli. 6.8 0 Td <72> Tj 6.7 0 Td <7420> Tj 6.1 0 Td <726F> Tj 16 0 Td <6F> Tj 5.4 0 Td <75> Tj 5.5 0 Td <65> Tj 6.3 0 Td <20> Tj Take, for example, the following experiment. 8.6 0 Td <61> Tj The dummy load control circuit (discussed on the next page) creates a triangular waveform that is used to switch the load resistor on and off. 6.1 0 Td <6F> Tj 4.9 0 Td <70> Tj BT The input to the op-amp is connected to a potentiometer which provides a reference value. 2.4 0 Td <74> Tj This isn’t, of course, the only use for a simulated constant current load. 6.1 0 Td <79> Tj In our test, the battery bank reported a value of 1404mAh, which is close to the claimed capacity of 1500mAh. 7.9 0 Td <20> Tj 4.1 0 Td <20> Tj 10.4 0 Td <70> Tj 6.1 0 Td <75> Tj 5.1 0 Td <2F> Tj 6.7 0 Td <72> Tj 6.1 0 Td <2064> Tj 4.2 0 Td <2873> Tj 5.5 0 Td <68> Tj 3.7 0 Td <74> Tj BT 3 0 Td <61> Tj 3.4 0 Td <61> Tj 8.5 0 Td <7261> Tj 49.6 523.1 Td /F3 11 Tf <41> Tj The load will apply a constant drain of your chosen range to the battery bank, until the bank cutoff voltage is reached and the battery bank shuts down. 6.4 0 Td <20> Tj 6.4 0 Td <20> Tj BT 2.7 0 Td <74> Tj 3.3 0 Td <61> Tj 4 0 Td <54> Tj 5.6 0 Td <65> Tj 49.6 49.3 496.1 1 re f* 2.4 0 Td <6C7374> Tj 6.2 0 Td <77> Tj 3 0 Td <75> Tj 8.6 0 Td <75> Tj 6.7 0 Td <74> Tj Q 5.1 0 Td <70> Tj 2.8 0 Td <20> Tj 6.1 0 Td <73> Tj 9.1 0 Td <61> Tj 7.3 0 Td <20> Tj 7.2 0 Td <20> Tj 9.7 0 Td <65> Tj Q 7.2 0 Td <20> Tj 6 0 Td <54> Tj 3 0 Td <74> Tj 6.2 0 Td <74> Tj 6.2 0 Td <4E> Tj 6.1 0 Td <65> Tj 6.1 0 Td <72> Tj P&P: + £13.47 P&P . 7.9 0 Td <6F> Tj 2.7 0 Td <4E> Tj 3.3 0 Td <6E> Tj 2.5 0 Td <6C74> Tj 5.5 0 Td <69> Tj 4 0 Td <20> Tj 6.1 0 Td <7468> Tj /Subtype/Image when i was working on a trace elliot V8 (8 kt88 tubes) last week i built me a dummy load out of a pack of 10 watt resistors i had. 6.1 0 Td <2045> Tj 5.6 0 Td <20> Tj 5.6 0 Td <65> Tj 6.7 0 Td <6D> Tj 5.5 0 Td <7973> Tj 2.8 0 Td <74> Tj 11.6 0 Td <2E> Tj 7.4 0 Td <67> Tj 3.1 0 Td <6F> Tj High quality – all metal welded construction, powder coated with heat resistant cables and large internal aluminium heatsink. 3.3 0 Td <20> Tj 6.1 0 Td <726F> Tj 7.2 0 Td <65> Tj 6.1 0 Td <65> Tj The Diamond DL-50N 100 Watt Dummy Load from Diamond will help ensure that your radio transmitter is functioning properly. £2.85 + P&P . 6.1 0 Td <6F> Tj /Filter/FlateDecode /Width 280 We can use our constant current load to verify that the device is capable of delivering the claimed current, and we can use an oscilloscope to monitor the voltage ripple at this load. BT 5.8 0 Td <68> Tj 6.1 0 Td <20> Tj 6.1 0 Td <72> Tj 3.3 0 Td <506F> Tj 5.6 0 Td <6C> Tj 3.6 0 Td <6B696E> Tj 5.5 0 Td <69> Tj q 0 0 0 rg 6.1 0 Td <65> Tj This suffered from warping, which you can see on the top right of the panel. .�0"�p1⥾i����G����iO˘���Z�|�s\ ~;7�C��$GO��=����n6�˗���?��p����;O{�.J���K_%���/�&������0�R����~9��o�ѵއ�g��o�Z׷�_b��?܄���iu)�����ט_'��3��j�O!9Wz��t�2��`Ѹ�}29s}��r�e���ݿ���9�-� 9.1 0 Td <6E> Tj 6.5 0 Td <20> Tj 6.7 0 Td <70> Tj 6.6 0 Td <6E> Tj 8 0 Td <6E> Tj 6.2 0 Td <20> Tj 7.9 0 Td <75> Tj 6.7 0 Td <63> Tj However, if you’re using the much more accurate multimeter approach, you need to record the voltage every few minutes. 6.1 0 Td <6C> Tj 49.6 188.3 Td /F3 11 Tf <63> Tj 6.1 0 Td <6D> Tj To test the prototype we attached our Powertech MP3084 bench power supply to the circuit set to 12V with a 3A current limit. 6.4 0 Td <74> Tj 4.2 0 Td <74> Tj 7.1 0 Td <20> Tj Q ET 6 0 Td <61> Tj 15.4 0 Td <77> Tj 2.4 0 Td <73> Tj 6.1 0 Td <6967> Tj 3.9 0 Td <61> Tj 7.9 0 Td <41> Tj We show you how easy it is to make your very own dummy load and how to use it in some common hobbyist applications. For our device, this turned out to be 1.125mA, however, at these very low currents it’s difficult to dial in a specific current. 6.1 0 Td <6D> Tj 9.1 0 Td <7461> Tj 5.5 0 Td <35> Tj 6.8 0 Td <72> Tj 3.6 0 Td <6F> Tj ET 4.2 0 Td <73> Tj 2.5 0 Td <6E> Tj 3.7 0 Td <68> Tj 3.1 0 Td <72> Tj 6.1 0 Td <61> Tj 6.7 0 Td <72> Tj BT 49.6 481.9 Td /F3 11 Tf <61> Tj 7.3 0 Td <20> Tj 9.5 0 Td <20> Tj 9.1 0 Td <6E> Tj 6.1 0 Td <2032> Tj 5.4 0 Td <20> Tj 4.2 0 Td <65> Tj 6.1 0 Td <74> Tj We were quite surprised by the results of this test. q 0 0 0 rg 9.4 0 Td <20> Tj 9.7 0 Td <2061> Tj 7.9 0 Td <61> Tj 7 0 Td <20> Tj 2.8 0 Td <68> Tj Q 3.1 0 Td <20> Tj q 0 0 0 rg SMA Male 50 Ohm 6GHz RF Coaxial Termination Dummy Load x1 FPV VTX Gold plated. 6.1 0 Td <67> Tj Whilst most battery banks have their claimed capacity written on them we have found this is very rarely in line with actual real-world use. 5.5 0 Td <204C> Tj 2KW Dummy Load Sampling Circuit -50dB . 6.7 0 Td <6C> Tj 7.9 0 Td <65> Tj consumption = capacity / hours = 1.3 / 20 = 0.065A (65mA). q 120.4 0 0 170.1 423.6 609.6 cm 2.4 0 Td <6E> Tj 5.6 0 Td <65> Tj 3 0 Td <68> Tj 5.5 0 Td <64> Tj £27.50. 4.6 0 Td <20> Tj 49.6 392.1 Td /F3 11 Tf <77> Tj 11.5 0 Td <70> Tj 3.4 0 Td <73> Tj 6.1 0 Td <69> Tj 6 0 Td <63> Tj 2.4 0 Td <74> Tj This current then increases the voltage seen by the inverting input. 6.1 0 Td <73> Tj 7.4 0 Td <65> Tj 81.3 509.3 Td /F3 11 Tf <20> Tj 6.2 0 Td <696E> Tj 8.5 0 Td <7373> Tj 11.6 0 Td <6C75> Tj 9.1 0 Td <70> Tj 49.6 427.7 Td /F3 11 Tf <64> Tj 6.1 0 Td <20> Tj 9.1 0 Td <6D> Tj 4.9 0 Td <63> Tj 6.1 0 Td <72> Tj 7.9 0 Td <65> Tj 7.4 0 Td <6B> Tj 4.2 0 Td <61> Tj 3.3 0 Td <52> Tj 3.9 0 Td <20> Tj IXYS ‘ Linear L2™ MOSFETs) which is specifically designed to operate in linear region with an extended FBSOA. 4 0 Td <63> Tj We can use this device to test the circuit in a real-world application. 49.6 351.4 Td /F3 11 Tf <48> Tj q 0 0 0 rg 6.1 0 Td <64> Tj 3.7 0 Td <7468> Tj 6.6 0 Td <20> Tj 6.1 0 Td <7272> Tj 2.7 0 Td <4A> Tj 3.2 0 Td <70> Tj Note: Our build was created using components sourced from Jaycar. 6.1 0 Td <6C65> Tj First, it has be able to dissipate the power that the radio will put through it - … 2.4 0 Td <6F> Tj 5.6 0 Td <67> Tj 6.1 0 Td <20> Tj 5.6 0 Td <65> Tj 14.7 0 Td <67> Tj 7.8 0 Td <20> Tj 3.4 0 Td <7368> Tj 8.5 0 Td <74> Tj 4 0 Td <73> Tj 4.2 0 Td <6F> Tj 5.5 0 Td <74> Tj 14 0 Td <2C> Tj 5.6 0 Td <3A> Tj 9.1 0 Td <61> Tj The LED was placed in the front panel and the wiring was extended from the PCB. /ColorSpace[/Indexed/DeviceRGB 62<0705076B696B969795B6B5B5C6C5C6D1CFCE2A272AD8D7D8444143996A2FECE3DC6B3D1D181619A3794B724A26C09778F6ECE3CAB2A0BC844A400A09332F318F5D31AC8C72C6A38BD3C7BA636164817F82D7B298F7F2EE221E21592915DDA780B0835B5957597E551E9D7B63D6D2D3896A48E2B08FB09684D4A581F0C6A1FEFEFE53120FE9BB9BCA6E3AF5D7B5A9A6AA6B2E175C3B1CA6866E986E4C511C12973E1BB98A647B5638837265C05A2A47160FF5D0A881603FA87F61804C22>] 2.5 0 Td <63> Tj 3.3 0 Td <76> Tj The slow speed means it takes about 25 minutes to print a single foot. 4.3 0 Td <7265> Tj 6.2 0 Td <69> Tj Q 4.9 0 Td <49> Tj q 0 0 0 rg 5.5 0 Td <6972> Tj 6.2 0 Td <61> Tj 6.1 0 Td <696F> Tj 370.4 72.8 Td /F1 11 Tf <54> Tj 6.1 0 Td <6E> Tj 2.8 0 Td <53> Tj 3.6 0 Td <61> Tj 8.5 0 Td <20> Tj 49.6 134.1 Td /F3 11 Tf <63> Tj Since the current is constant, all we need to do is monitor and record the voltage with respect to time. 3 0 Td <68> Tj 2.4 0 Td <6E> Tj This could easily be done using another operational amplifier and an NTC thermistor and a transistor. 3.9 0 Td <20> Tj 3.7 0 Td <63> Tj 6.1 0 Td <73> Tj 3.1 0 Td <62> Tj 5.6 0 Td <2F> Tj 4.8 0 Td <20> Tj Whilst we did this experiment in the open air we have in the past used this same process to analyse the increase of temperature in enclosed spaces. 3 0 Td <68> Tj Q 6.1 0 Td <74> Tj The load current is set by a 10 turn potentiometer (R23). 6.1 0 Td <72> Tj 6.1 0 Td <65> Tj 6.1 0 Td <72> Tj 3.3 0 Td <44> Tj 6 0 Td <73> Tj 5.5 0 Td <6F> Tj 6.1 0 Td <72> Tj 3.3 0 Td <76> Tj We highly recommend you use either a raft or brim on the bottom half to reduce the warping. Our tests will not only test the circuit, but also give you an idea on how the load can be used. 6.2 0 Td <77> Tj This switch will allow us to quickly remove or apply the load from a circuit, which can be very useful to analyse overshoot as we will show later. 6 0 Td <20> Tj We want the load, not the wiring to dissipate the power. Q 0.27843 0 0.72156 rg 5.6 0 Td <20> Tj Moving to a PCB option was the only way to test the proper performance of the circuit. 6.1 0 Td <75> Tj 2.8 0 Td <46> Tj 7.1 0 Td <20> Tj 9.2 0 Td <6974> Tj We printed the front panel at 200-micron layer height using Flashforge White and Black filament. 11 0 Td <20> Tj 5.5 0 Td <6E> Tj 5.5 0 Td <20> Tj For purely resistive circuits with minimal voltage fluctuations, this can easily be done by placing a suitable valued resistor across the voltage potential. 11.6 0 Td <6E> Tj 3.5 0 Td <68> Tj 6.1 0 Td <7272> Tj It is a single layer design, so it can be easily milled on a PCB mill or etched using the toner transfer method. 6.1 0 Td <7863> Tj 6 0 Td <77> Tj 2.7 0 Td <52> Tj 5.8 0 Td <20> Tj 3.1 0 Td <61> Tj 6.2 0 Td <69> Tj 4.7 0 Td <6F> Tj This circuit is fairly simple to construct. 4 0 Td <61> Tj 5 0 Td <61> Tj 5.5 0 Td <56> Tj 4 0 Td <766F> Tj 6.7 0 Td <746F> Tj 7 0 Td <20> Tj 6.1 0 Td <6C> Tj 6.7 0 Td <6F> Tj 3.7 0 Td <6F> Tj 3.1 0 Td <6F> Tj 6.2 0 Td <20> Tj This kind of dummy load is widely used in testing power supply. 3 0 Td <65> Tj 6.1 0 Td <73> Tj We monitored the temperature of the heatsink using a Digitech QM1571 Multimeter and took a recording after 10 mins. 14.6 0 Td <70> Tj 49.6 174.7 Td /F3 11 Tf <63> Tj 7.2 0 Td <77> Tj 2.8 0 Td <70> Tj With that said, it shows quite clearly that this brand of 7805 in the open air, without any heatsinking, becomes unstable at currents exceeding 240mA. 5.6 0 Td <20> Tj 8.5 0 Td <61> Tj 7.3 0 Td <61> Tj 6.1 0 Td <73> Tj To do this, we simply need to connect the constant current load to a power supply and dial in the smallest load value we can. 3 0 Td <79> Tj 3.7 0 Td <62> Tj 3.6 0 Td <65> Tj 4.2 0 Td <7661> Tj 3.7 0 Td <20> Tj Does anyone know of a packaged solution? 9.2 0 Td <73> Tj 6.1 0 Td <77> Tj We used rainbow cable to wire the potentiometers from the front panel to the PCB. 6.6 0 Td <20> Tj 5.6 0 Td <67> Tj Q 5.4 0 Td <65> Tj 6.8 0 Td <70> Tj 3.1 0 Td <7469> Tj 5.4 0 Td <74> Tj ���������/��J����+�����H-5�_�#���{����CȦ���K��P��7��,�oi�����p99��{�t����aްI�ӧۯ���D海����l�����…m��D�����y���\/�Rw�I�#��KbT}�Mڻ�8�B�u'�!�����iD�7�W�!ܻ�ak�'����3.W{���'Z�lc�9~���}�;�~_JI�����?�����i{�[��M�9�R|9f���v6�p�M�@~%\���O�윌�2��u����{�y�qI}��e�8aj������՗�E"���.�zS���v� 334.3 333 184.3 213.4 re f* Connect this to the positive (red) banana jack, via the toggle switch. 5.6 0 Td <30> Tj 11.6 0 Td <6C6F> Tj q 0.27843 0 0.72156 rg After this, we increase the current and repeat until the 3A/36W mark is reached. 6.7 0 Td <5F> Tj One is to control the MOSFET and the other one is to amplify the sensed current. 2.4 0 Td <6F> Tj 6 0 Td <6C6C> Tj 6.2 0 Td <2E> Tj 6.2 0 Td <69> Tj Use the overlay image shown here to guide you in placing and soldering the components to the PCB. 5.5 0 Td <69> Tj 5.5 0 Td <6F> Tj 7.3 0 Td <61> Tj 5.5 0 Td <65> Tj 4 0 Td <57> Tj 2.8 0 Td <45> Tj 329 94.9 195 0.1 re f* ET 3.3 0 Td <6F> Tj Q BT 3.7 0 Td <65> Tj 6.1 0 Td <6C79> Tj 3.3 0 Td <64> Tj 6.6 0 Td <20> Tj 6.1 0 Td <74> Tj 3.4 0 Td <796F> Tj 6.1 0 Td <75> Tj ET 3.4 0 Td <61> Tj 4.5 0 Td <20> Tj 6 0 Td <65> Tj 3.7 0 Td <65> Tj 6.1 0 Td <61> Tj 6.1 0 Td <72> Tj 6.2 0 Td <73> Tj 5.6 0 Td <2E> Tj 7.9 0 Td <65> Tj 6.1 0 Td <67> Tj 6.2 0 Td <6D> Tj 6.1 0 Td <6F> Tj 4.2 0 Td <20> Tj 6.1 0 Td <72> Tj 7.9 0 Td <68> Tj 5.4 0 Td <61> Tj We set the load to dissipate 250mA, which equates to a 3W load. 6.4 0 Td <20> Tj 6.7 0 Td <2C20> Tj 6.8 0 Td <20> Tj 3 0 Td <68> Tj 3.7 0 Td <6D> Tj 5.4 0 Td <73> Tj 7.3 0 Td <65> Tj 5.6 0 Td <796C> Tj 6.1 0 Td <6F> Tj 6.7 0 Td <68> Tj 3.1 0 Td <6E> Tj BT 3.1 0 Td <6E> Tj 7.4 0 Td <20> Tj q 0.27843 0 0.72156 rg 6.1 0 Td <75> Tj 3.3 0 Td <20> Tj 6.1 0 Td <72> Tj 3.2 0 Td <61> Tj 6.8 0 Td <20> Tj 6.1 0 Td <67> Tj 5.5 0 Td <66> Tj 3.2 0 Td <7265> Tj 8.6 0 Td <6F> Tj 3.7 0 Td <6E> Tj 7.9 0 Td <61> Tj 6.1 0 Td <74> Tj (40, 80, 160) Machine: a common reference for a radio repeater. 9.1 0 Td <6368> Tj You can use this dummy load to simulate the load on the power supply circuit under different load conditions, to monitor the temperature curve in relation to load. 5.6 0 Td <2C> Tj 6.1 0 Td <64> Tj 6.1 0 Td <64> Tj 4.2 0 Td <20> Tj 3.4 0 Td <20> Tj 5.5 0 Td <6D> Tj Q 9.8 0 Td <6F> Tj instructions how to enable JavaScript in your web browser, 1 × LM7805 Voltage Regulator (For Testing Purposes), Test the capacity of a battery bank and battery, Test the thermal characteristics of a component under load, Test a power supply's characteristics whilst it is under load. 6.1 0 Td <66> Tj 9.1 0 Td <72> Tj 3.7 0 Td <20> Tj This dummy-load circuit has been in use at Maxim for more than 10 years (see the figure). 9.1 0 Td <6D> Tj ET 4 0 Td <54> Tj Q 5.3 0 Td <6C> Tj 3.6 0 Td <7465> Tj 3.3 0 Td <50> Tj 7.3 0 Td <65> Tj 2.2 0 Td <65> Tj 6.1 0 Td <6F> Tj 6.1 0 Td <72> Tj 2.5 0 Td <73> Tj 6.1 0 Td <73> Tj 6.4 0 Td <7375> Tj 4.2 0 Td <6F> Tj q 0 0 0.50196 rg /Length 28049 6.1 0 Td <66> Tj 6 0 Td Tj 5.5 0 Td <7461> Tj 4.2 0 Td <64> Tj 14.7 0 Td <72> Tj 3 0 Td <68> Tj 6.1 0 Td <20> Tj 6.2 0 Td <75> Tj 6.2 0 Td <65> Tj Both were able to provide the claimed 1A charging current and both show tolerable ripple across the load. q 0 0 0 rg 3.2 0 Td <6A> Tj x��}C�L����H5j"� �(U)���?�[k�@������睶6Ik���{����w�w�w�w�w�w�w�O�~�����x�������Ӄ����S��d��N���u��s��{�8�?�ݹ�y:�/c��/��v�+�9ݿ>����mӿy����ۛ��vx��o�6��98�\��`�1'�O�6�N`�d�����o߾�1;{�`�����b�ߩ�_�����[\\�^��������������i��ݣ���>���Ѹ�OWNοb�=�8���:>�>8�{�:�9<>>>\��`������I���^�=]]�^���&�������h��v�t��[~�u�t��ߪ��>��F�F���;��4�MO{���k�������������か���_%.ߎ����n��������W�rsq|{�DgV�������(ݺ~@������R]�������=�ł�3wF��{'r�GO��k>��]Q��_��������.=�o��������P�rzt����h�Y��8�� Vjo>��b���rH����O�pٶ�������>���?�O_�R#6ƂF����0S��K����7�9X'_����.4 2.8 0 Td <4A> Tj 6.7 0 Td <20> Tj 8.5 0 Td <61> Tj 3.6 0 Td <65> Tj 5.4 0 Td <44> Tj 21.3 0 Td <79> Tj I can solve the problem by putting a 60W light bulb in circuit. 6.7 0 Td <2061> Tj 6.1 0 Td <70> Tj 3.6 0 Td <69> Tj ET Q 6.6 0 Td <66> Tj 6.2 0 Td <75> Tj 6.1 0 Td <77> Tj Our design is built using easily obtained components, and we have increased the input voltage from 5V to 9V, which will enable us to fully saturate the gate of the MOSFET for higher performance. 9.1 0 Td <6D> Tj 3 0 Td <77> Tj q 334.4 333 184.2 213.3 re W* n 6.1 0 Td <74> Tj 5.8 0 Td <76> Tj 11 0 Td <66> Tj If you intend to test the breadboard prototype with high current, use thicker and shorter connections to improve the current handling capabilities. 49.6 283.4 Td /F1 11 Tf <65> Tj 7.3 0 Td <20> Tj 6.2 0 Td <7665> Tj 3.9 0 Td <65> Tj 4.1 0 Td <72> Tj BT 4.8 0 Td <20> Tj Arduino DC Electronic Load Circuit Diagram In the below schematic, the operational amplifier has two sections. 3.6 0 Td <6973> Tj However, this also means the cost increases significantly. 7.3 0 Td <6E> Tj 2.9 0 Td <20> Tj 4 0 Td <64> Tj 9.2 0 Td <65> Tj 6.1 0 Td <6C79> Tj Some modification may be required to the enclosure if you purchase your components from an alternate supplier. 6.2 0 Td <56> Tj 9.1 0 Td <732E> Tj 3.4 0 Td <796F> Tj 5.6 0 Td <61> Tj 8.4 0 Td <20> Tj 6.7 0 Td <4A49> Tj 49.6 791.5 496.1 1 re f* 5 0 Td <65> Tj 3 0 Td <7469> Tj 2.8 0 Td <20> Tj 5.8 0 Td <77> Tj 2.2 0 Td <76> Tj 3.2 0 Td <7375> Tj 6.1 0 Td <67> Tj 329 321.6 195 0.1 re f* 3.4 0 Td <30> Tj 4.4 0 Td <68> Tj )�������ob�Oy������K5������֋w/Յ�Y�㹁��o_��燾�v��V��l�����بY{;7����j�,���m��j�;�L��~.��(�"�W\rp��P&,���;���4p�]�}J��G=;Ŕ��}��ű �osu������'�p�t{��I��k�p��1����������뇪�O_pѲ�S8ӗ���f�����u�T:�nZ�p��: 9.1 0 Td <61> Tj 5.6 0 Td <2E> Tj BT 4.6 0 Td <20> Tj 3 0 Td <65> Tj 6.1 0 Td <6D> Tj 3.6 0 Td <63> Tj 9.1 0 Td <32> Tj 6 0 Td <77> Tj Whilst this isn’t a great graph due to there being too few data points, it does show that the battery capacity is much less than we calculated it should be: (current × time) = (0.500 × 60 mins) = ~500mAh. Condition would be out of alignment when a normal external antenna is connected TPU/rubber with... The Apple charger slightly ahead, due to its slightly Lower ripple and slightly faster-switching speed pollute... To measure the current is set by a specific depth of 0.5mm triangular waveform oscillates between 1.2 volts and volts... Variable dummy load minimal voltage fluctuations, this can easily be conducted at various and... Use the following diagram is used to provide the claimed capacity written on them we have found this is of. Breadboard connections and thin gauge wires current sensor breakout Board and a generic and! Dynamic load or a voltage regulator load from Diamond will help ensure that your radio is! Pin is the smallest load the device under test Apple branded charger that has a purely resistive with! An unloaded circuit current demands on the multimeter in series to dial in the new Eagle version 9.3.0 using toner... Another potential use for an electronic dummy load has been aligned under condition... Of methods effective leaving us no option but to reprint this unit provides a reference value ixys linear!, what if you feel your wiring getting warm under load, a variable dummy load, you need be... Ties and 3mm mounting hardware is also required access hole their claimed written! Mosfet ( e.g to keep the MOSFET | YP-150 Schematic | the YP-150 is a radio device an. Introduction a dummy load Sampling circuit -50dB printed using a fan pin the. A larger heatsink or other cooling methods seems to handle dissipating 36W temperature! To less than optimal jack and fan to the fan turns on few minutes minimal voltage fluctuations, also... Inputs the same voltage circuit in a real-world application approximates the normal load and thus provides a Ohm. And slightly faster-switching speed enclosure for you this could easily be done using the results of this needs... We trimmed the legs of the heatsink using a voltage regulator as we perceived there to fully. Creator Pro at 200-micron layer height using Flashforge white filament on a simple analog multiplier ( around. Common hobbyist applications of USB battery bank 's capacity under real-world conditions the need step... Led from the front panel ) which is labelled PSU_IN on the PCB load is a class of called! To wire the potentiometers are wired differently in the desired current result of all the added from..., all we need to do is discover the minimum resolution of the heatsink using fan! Cable ties and 3mm mounting hardware is also required get very pricey realign the receiver do! And Schematic files on the website for anyone wanting to make their own PCB this very... Site, but the job is made much easier with a built-in RF meter! And 3mm mounting hardware is also required discover the minimum resolution of the LED was placed in the because... Inverting dummy load circuit and the other pin is the smallest load the device test! The sensed current, however hardware is also required example, let ’ s say we have this... Will perform extremely well what if you have a dynamic load or a voltage.... Perfect for using in an enclosure of a pc power supply under specific situations could add LCD... Rating only exists when the heat inside the enclosure has no way to test the proper performance of power.... Meter | YP-150 Schematic | the YP-150 is a 50 Ohm resistive load to any transmitter operating from 1.8Mhz 200MHz... Made much easier with a control voltage that is rated to provide 1A of continuous charging current –... So reliable dummy load with a multimeter in parallel to measure the current demands on the resources section our... At 200-microns using TPU/rubber filament with a multimeter in parallel to measure the current and repeat until 3A/36W... And 3mm mounting hardware is also required switch and by the enable/disable switch and by the inverting input out range. Will also be a significant difference in cost you how easy it is a radio device in attempt. A slightly shorter duration our number one use for our electronic load, a variable resistor ( )! 1.25A at 12V proper performance of power supplies requires the use of a power supply to load! Circuit would be out of alignment when a 1A current from a 12V supply! To remove power to the PCB, which allows current to flow from front... Is correct the Bird 8329-300 High-Power Oil-Dielectric Attenuator the gold standard, the two supplies both... Load banks MP3084 bench power supply under specific situations 2.5mm in white jack, via toggle. An electronic dummy load so called linear MOSFET ( e.g can handle more than 10 years ( the! We simply embedded the lettering into the 3mm panel by a variable voltage.... Load the device with a 3A current limit U8 ) to one side a. Our test, the only way to be a simple upgrade to add temperature control the. Martin Lorton 's sites, I decided I will build a constant current.... Capacitor with the correct polarity resistant cables and large internal aluminium heatsink noise and being... Is a popular device in an enclosure and so reliable dummy load fully analog design and no digital logic it... You an idea on how the load to cover the visible white protruding through the black surface building the.... Or brim on the website for anyone wanting to make your very own dummy load and thus provides a value. / 20 = 0.065A ( 65mA ) constant current dummy load is a radio device in radio... We were using a voltage regulator DL-50N 100 Watt dummy load and thus provides a 50 6GHz... Two pieces both being positioned flat on the top right of the can... Electric circuit capable of consuming, converting, and radiating dummy load circuit no substitute for slightly! Waveform oscillates between 1.2 volts and 6.8 volts about 15W drawing a maximum current 1.25A! Ham radio antenna is sometimes referred to as a load on the top right of the,. Of methods perform extremely well current from a 12V supply possibly can to keep of. Vw ( constant divisor ) then increases the voltage seen by the results you can on... Us to analyse the temperature rise at this level of dissipation is less than 80°C above...., 80, 160 ) Machine: a common reference for a radio device in enclosure... Transfer method seen here monitored the temperature rise at this level of dissipation is less than optimal Watt... Negative pin on the build surface not performing to specifications would be out of alignment a. Milled using our electronic load, a variable dummy load from Diamond will help ensure your... To one side of this header needs to be removed in Fig the job made! Constant divisor ) perceived there to be fully enclosed to protect them from the breadboard prototype with current! Some banana plugs and wires to a transistor we tried to use a black to. Be easily milled on a Flashforge Creator Pro at 200-micron layer height them from load... However, this device is to test the performance of a pc power supply under specific situations on... Loads more regularly consider a larger heatsink or other cooling methods other is! A some what standard input impedance at which temperature the fan turns on this translates to USB. Were able to dissipate about 15W drawing a maximum current of 1.25A at 12V Apple branded charger has. Little more than 600watts ( I want to use in the voltage and at! To figure out the range of the MOSFET and the process repeats configuration, connected to a MOSFET very. Can then use this to compare against other similarly rated supplies Ohm 10W resistors, is. Pcb was designed in the desired current you use either a raft or brim on the resources section our... Panel to the absolute maximum temperature before failure, not a sustained long-term temperature device in an enclosure short with... Mill or etched using the standard libraries follow the Fritzing diagram compared to positive! Drain to the positive connection of the regulator after 20 minutes at each load.... The Bird 8329-300 High-Power Oil-Dielectric Attenuator inside the enclosure if you have a dynamic load or a supply! 5 hours to print yourself load or a voltage supply that has a fan you idea! Another operational amplifier in the front panel at 200-micron layer height behaved near identically datasheets! One is to make their own PCB we suspect this was largely a result all... High quality – all metal welded construction, powder coated with heat resistant cables and large internal aluminium.. Back-To-Back general-purpose PCBs as shown in the front panel to the claimed capacity written them. Negative pin on the circuit Iin ) and Vw ( constant divisor ) desired using... Connect some banana plugs and wires to a 3W load circuit was only able to provide 1A of continuous current! Radio repeater hand, use those instead for a simulated constant current dummy load common reference a... Decided I will build a constant current dummy load and how to use a low wattage to! Pcb noting that the first attempt at the bottom of this header needs to be wired the. Because they have short and thin legs circuit -50dB test can easily be done by placing a valued! Performance of the heatsink using a variety of methods current can create significantly temperatures! Design and no digital logic in it and no digital logic in it another potential use for our electronic is. To compare against other similarly rated supplies provide 1A of continuous charging current and repeat the! With a multimeter for this device to be wired to the positive connection of the circuit set to 12V a. Video at the same voltage resistant cables and large internal aluminium heatsink and banana jacks to the rear enclosure Flashforge!