Electromagnetic therapy device

Circuit working principle The electromagnetic therapy instrument circuit consists of power switch Sl, electromagnetic coil Ll, L2, rectifier diode VDl-VD5, light-emitting diode VL, resistor Rl-R4, potentiometer RP, thyristor VT, bidirectional trigger diode V, capacitor Cl- C3 and constant magnetic / pulse selection switch S1, as shown in Figure 9-13.

Turn on the power switch S1, the AC 220V voltage is limited by L1 and L2, and VDl-VD4 is rectified and added to the anode and cathode of VTD (the current flowing through L1 and L2 is small). At the same time, the DC voltage rectified by VDl-VD4 is also charged to C2 by VD5. When the voltage across C2 is charged to a certain value, V is turned on, so that VT is triggered to conduct, and the currents of L1 and L2 are increased to generate a constant magnetic field to treat the patient's lesion.
When S2 is turned on, C3 is connected in parallel with C2 through S2, and Ll and 愧 can generate low frequency magnetic pulses.
VL lights up when the electromagnetic therapy device is working.
Adjusting the resistance of the RP can change the frequency of the magnetic pulse.
Component selection
Rl-R4 selects 1/4W metal film resistor for use.
RP uses an organic solid potentiometer.
Cl and C2 use CBB capacitors or polyester capacitors with a withstand voltage of 400V; C3 selects aluminum electrolytic capacitors with a withstand voltage of 5OV or more.
VDl-VD4 selects 5A, 400V silicon rectifier diodes; VD5 selects 1N4007 silicon rectifier diodes.
VL selects φ5mm LED.
V selects DB3 type bidirectional trigger diode.
VT uses 6A, 600V thyristors.
Both Ll and L2 use an enamel wire of φO.25 mm around a core of φ8 mm x 5 Omm around 3800-4000 。.
S1 selects 10A, 220V power switch; S2 selects 5A, 220V single pole switch.